|February 29 in recent years|
February 29, also known as leap day or leap year day, is a date added to most years that are divisible by 4, such as 2008, 2012, 2016, 2020, and 2024. A leap day is added in various solar calendars (calendars based on the Earth's rotation around the Sun), including the Gregorian calendar standard in most of the world. Lunisolar calendars (calendars based on the rotation of the Moon) instead add a leap or intercalary month.
In the Gregorian calendar, years that are divisible by 100, but not by 400, do not contain a leap day. Thus, 1700, 1800, and 1900 did not contain a leap day; neither will 2100, 2200, and 2300. Conversely, 1600 and 2000 did and 2400 will. Years containing a leap day are called leap years. February 29 is the 60th day of the Gregorian calendar in such a year, with 306 days remaining until the end of the year. In the Chinese calendar, this day will only occur in years of the monkey, dragon, and rat.
A leap day is observed because a complete revolution around the Sun takes approximately 6 hours longer than 365 days (8,760 hours). A leap day compensates for this lag, realigning the calendar with the Earth's position in the Solar System; otherwise, seasons would occur earlier than intended in the calendar year. Originally, the Julian calendar added a leap day every four years, but this turned out to add too many days, making the equinoxes and solstices shift gradually to earlier dates. As the shifting became noticeable (by the late 16th century the vernal equinox had drifted to March 11) the Gregorian calendar was introduced both to shift it back by omitting several days, and to reduce the number of leap years via the "century rule" to keep the equinoxes more or less fixed and the date of Easter consistently close to the vernal equinox.
Although most modern calendar years have 365 days, a complete revolution around the Sun (one solar year) takes approximately 365 days and 6 hours. An extra 24 hours thus accumulates every four years, requiring that an extra calendar day be added to align the calendar with the Sun's apparent position. Without the added day, in future years the seasons would occur later in the calendar, eventually leading to confusion about when to undertake activities dependent on weather, ecology, or hours of daylight.
A solar year is actually slightly shorter than 365 days and 6 hours (365.25 days). As early as the 13th century it was recognized that the year is shorter than the 365.25 days assumed by the Julian calendar: the Earth's orbital period around the Sun was derived from the medieval Alfonsine tables as 365 days, 5 hours, 49 minutes, and 16 seconds (365.2425 days). The currently accepted modern figure is 365 days, 5 hours, 48 minutes, 45 seconds. Adding a calendar day every four years, therefore, results in an excess of around 44 minutes for those four years, or about 3 days every 400 years. To compensate for this, three days are removed every 400 years. The Gregorian calendar reform implements this adjustment by making an exception to the general rule that there is a leap year every four years. Instead, a year divisible by 100 is not a leap year unless that year was also exactly divisible by 400. This means that the years 1600, 2000, and 2400 are leap years, while the years 1700, 1800, 1900, 2100, 2200, 2300, and 2500 are common years.
Modern (Gregorian) calendar
The Gregorian calendar repeats itself every 400 years, which is exactly 20,871 weeks including 97 leap days. Over this period, February 29 falls on Sunday, Tuesday, and Thursday 13 times each; 14 times each on Friday and Saturday; and 15 times each on Monday and Wednesday. Excepting when a century mark that is not a multiple of 400 intervenes, consecutive leaps days fall in order Thursday, Tuesday, Sunday, Friday, Wednesday, Monday, and Saturday; then repeating with Thursday again.
Early Roman calendar (of Numa Pompilius)
The calendar of the Roman king Numa Pompilius had only 355 days (even though it was not a lunar calendar) which meant that it would quickly become unsynchronized with the solar year. An earlier Roman solution to this problem was to lengthen the calendar periodically by adding extra days to February, the last month of the year. February consisted of two parts, each with an odd number of days. The first part ended with the Terminalia on the 23rd, which was considered the end of the religious year, and the five remaining days formed the second part. To keep the calendar year roughly aligned with the solar year, a leap month, called Mensis Intercalaris ("intercalary month"), was added from time to time between these two parts of February. The (usual) second part of February was incorporated in the intercalary month as its last five days, with no change either in their dates or the festivals observed on them. This followed naturally, because the days after the Ides (13th) of February (in an ordinary year) or the Ides of Intercalaris (in an intercalary year) both counted down to the Kalends of March (i.e. they were known as "the nth day before the Kalends of March"). The Nones (5th) and Ides of Intercalaris occupied their normal positions.
The third-century writer Censorinus says:
When it was thought necessary to add (every two years) an intercalary month of 22 or 23 days, so that the civil year should correspond to the natural (solar) year, this intercalation was in preference made in February, between Terminalia [23rd] and Regifugium [24th].
Later Roman calendar (Julian)
The leap day was introduced in Rome as a part of the Julian reform in the 1st century BC. As before, the intercalation was made after February 23. The day following the Terminalia (February 23) was doubled, forming the "bis sextum"—literally 'twice sixth', since February 24 was 'the sixth day before the Kalends of March' using Roman inclusive counting (March 1 was the Kalends of March and was also the first day of the calendar year). Although there were exceptions, the first day of the bis sextum (February 24) was usually regarded as the intercalated or "bissextile" day since the 3rd century AD. February 29 came to be regarded as the leap day when the Roman system of numbering days was replaced by sequential numbering in the late Middle Ages.
- 1504 – Christopher Columbus uses his knowledge of a lunar eclipse that night to convince Native Americans to provide him with supplies.
- 1644 – Abel Tasman's second Pacific voyage began.
- 1704 – Queen Anne's War: French forces and Native Americans stage a raid on Deerfield, Massachusetts Bay Colony, killing 56 villagers and taking more than 100 captive.
- 1712 – February 29 is followed by February 30 in Sweden, in a move to abolish the Swedish calendar for a return to the Julian calendar.
- 1720 – Ulrika Eleonora, Queen of Sweden abdicates in favour of her husband, who becomes King Frederick I on 24 March.
- 1752 – King Alaungpaya founds Konbaung Dynasty, the last dynasty of Burmese monarchy.
- 1768 – Polish nobles formed Bar Confederation.
- 1796 – The Jay Treaty between the United States and Great Britain comes into force, facilitating ten years of peaceful trade between the two nations.
- 1864 – American Civil War: Kilpatrick–Dahlgren Raid fails: Plans to free 15,000 Union soldiers being held near Richmond, Virginia are thwarted.
- 1892 – St. Petersburg, Florida is incorporated.
- 1912 – The Piedra Movediza (Moving Stone) of Tandil falls and breaks.
- 1916 – Tokelau is annexed by the United Kingdom.
- 1916 – Child labor: In South Carolina, the minimum working age for factory, mill, and mine workers is raised from twelve to fourteen years old.
- 1920 – Czechoslovak National assembly adopted the Constitution.
- 1936 – February 26 Incident in Tokyo ends.
- 1940 – For her performance as "Mammy" in Gone with the Wind, Hattie McDaniel becomes the first African American to win an Academy Award.
- 1940 – Finland initiates Winter War peace negotiations.
- 1940 – In a ceremony held in Berkeley, California, because of the war, physicist Ernest Lawrence receives the 1939 Nobel Prize in Physics from Sweden's Consul General in San Francisco.
- 1944 – World War II: The Admiralty Islands are invaded in Operation Brewer led by American General Douglas MacArthur.
- 1952 – The island of Heligoland is restored to German authority.
- 1960 – The 5.7 Mw Agadir earthquake shakes coastal Morocco with a maximum perceived intensity of X (Extreme), destroying Agadir, and leaving 12,000 dead and another 12,000 injured.
- 1964 – In Sydney, Australian swimmer Dawn Fraser sets a new world record in the 100-meter freestyle swimming competition (58.9 seconds).
- 1972 – Vietnam War: Vietnamization: South Korea withdraws 11,000 of its 48,000 troops from Vietnam.
- 1980 – Gordie Howe of the then Hartford Whalers makes NHL history as he scores his 800th goal.
- 1988 – South African archbishop Desmond Tutu is arrested along with 100 clergymen during a five-day anti-apartheid demonstration in Cape Town.
- 1988 – Svend Robinson becomes the first member of the Canadian House of Commons to come out as gay.
- 1992 – First day of Bosnia and Herzegovina independence referendum.
- 1996 – Faucett Flight 251 crashes in the Andes, all 123 passengers and crew died.
- 1996 – Siege of Sarajevo officially ends.
- 2000 – Second Chechen War: Eighty-four Russian paratroopers are killed in a rebel attack on a guard post near Ulus Kert.
- 2004 – Jean-Bertrand Aristide is removed as President of Haiti following a coup.
- 2008 – The United Kingdom's Ministry of Defence decides to withdraw Prince Harry from a tour of Afghanistan "immediately" after a leak led to his deployment being reported by foreign media.
- 2008 – Misha Defonseca admits to fabricating her memoir, Misha: A Mémoire of the Holocaust Years, in which she claimed to have lived with a pack of wolves in the woods during the Holocaust.
- 2012 – Tokyo Skytree construction completed. It is, as of 2016, the tallest tower in the world, 634 meters high, and second tallest (man-made) structure on Earth, next to Burj Khalifa.
A person born on February 29 may be called a "leapling", a "leaper", or a "leap-year baby". In non-leap years, some leaplings celebrate their birthday on either February 28 or March 1, while others only observe birthdays on the authentic intercalary date, February 29.
The effective legal date of a leapling's birthday in non-leap years varies between jurisdictions.
In New Zealand, a person born on February 29 is deemed to have their birthday on February 28 in non-leap years, for the purposes of Driver Licensing under §2(2) of the Land Transport (Driver Licensing) Rule 1999. The net result is that for drivers aged 75, or over 80, their driver licence expires at the end of the last day of February, even though their birthday would otherwise fall on the first day in March in non-leap years. Otherwise, New Zealand legislation is silent on when a person born on 29 February has their birthday, although case law would suggest that age is computed based on the number of years elapsed, from the day after the date of birth, and that the person's birth day then occurs on the last day of the year period. This differs from English common law where a birthday is considered to be the start of the next year, the preceding year ending at midnight on the day preceding the birthday. While a person attains the same age on the same day, it also means that, in New Zealand, if something must be done by the time a person attains a certain age, that thing can be done on the birthday that they attain that age and still be lawful.
In Taiwan (Republic of China), the legal birthday of a leapling is February 28 in common years:
- If a period fixed by weeks, months, and years does not commence from the beginning of a week, month, or year, it ends with the ending of the day which proceeds the day of the last week, month, or year which corresponds to that on which it began to commence. But if there is no corresponding day in the last month, the period ends with the ending of the last day of the last month.
Thus, in England and Wales or in Hong Kong, a person born on February 29 will have legally reached 18 years old on March 1. If he or she was born in Taiwan he or she legally becomes 18 on February 28, a day earlier. In the United States, according to John Reitz, a professor of law at the University of Iowa, there is no "... statute or general rule that has anything to do with leap day." Reitz speculates that "March 1 would likely be considered the legal birthday in non-leap years of someone born on leap day," using the same reasoning as described for the United Kingdom and Hong Kong.
There are many instances in children's literature where a person's claim to be only a quarter of their actual age turns out to be based on counting their leap-year birthdays.
A similar device is used in the plot of Gilbert and Sullivan's 1879 comic opera The Pirates of Penzance. As a child, Frederic was apprenticed to a band of pirates until his 21st birthday. Having passed his 21st year, he leaves the pirate band and falls in love. However, since he was born on February 29, his 21st birthday will not arrive until he is eighty-four, so he must leave his fiancée and return to the pirates.
This plot point was also used in a Sherlock Holmes story based on the Basil Rathbone era, where a friend of Dr. Watson's is a Baronet who is due to receive his inheritance on the New Year's Day of the year where his twenty-first birthday will be celebrated, only for the law to deprive him of the money as he was born on February 29; with the 84-year-old Baronet distraught at the news that 1900 is not a leap year, Holmes helps the Baronet fake his death long enough for his grandson — who is the appropriate age to receive the inheritance — to establish his claim and receive the money himself.
Notable 29 February births
Notable persons born on February 29:
- 1468 – Pope Paul III (d. 1549)
- 1576 – Antonio Neri, Florentine priest and glassmaker (d. 1614)
- 1692 – John Byrom, English poet and educator (d. 1763)
- 1724 – Eva Marie Veigel, Austrian-English dancer (d. 1822)
- 1736 – Ann Lee, English-American religious leader, founded the Shakers (d. 1784)
- 1792 – Gioachino Rossini, Italian pianist and composer (d. 1868)
- 1812 – James Milne Wilson, Scottish-Australian soldier and politician, 8th Premier of Tasmania (d. 1880)
- 1828 – Emmeline B. Wells, American journalist, poet, and activist (d. 1921)
- 1836 – Dickey Pearce, American baseball player and manager (d. 1908)
- 1852 – Frank Gavan Duffy, Irish-Australian lawyer and judge, 4th Chief Justice of Australia (d. 1936)
- 1860 – Herman Hollerith, American statistician and businessman, co-founded the Computing-Tabulating-Recording Company (d. 1929)
- 1884 – Richard S. Aldrich, American lawyer and politician (d. 1941)
- 1892 – Augusta Savage, American sculptor (d. 1962)
- 1896 – Morarji Desai, Indian civil servant and politician, 4th Prime Minister of India (d. 1995)
- 1896 – William A. Wellman, American actor, director, producer, and screenwriter (d. 1975)
- 1904 – Rukmini Devi Arundale, Indian dancer and choreographer (d. 1986)
- 1904 – Jimmy Dorsey, American saxophonist, composer, and bandleader (d. 1957)
- 1904 – Pepper Martin, American baseball player and manager (d. 1965)
- 1908 – Balthus, French-Swiss painter and illustrator (d. 2001)
- 1908 – Dee Brown, American historian and author (d. 2002)
- 1908 – Alf Gover, English cricketer and coach (d. 2001)
- 1908 – Louie Myfanwy Thomas, Welsh writer (d. 1968)
- 1916 – Dinah Shore, American singer and actress (d. 1994)
- 1916 – James B. Donovan, American lawyer (d. 1970)
- 1916 – Leonard Shoen, founder of U-Haul Corp. (d. 1999)
- 1920 – Fyodor Abramov, Russian author and critic (d. 1983)
- 1920 – Arthur Franz, American actor (d. 2006)
- 1920 – James Mitchell, American actor and dancer (d. 2010)
- 1920 – Michèle Morgan, French-American actress and singer
- 1920 – Howard Nemerov, American poet and academic (d. 1991)
- 1920 – Rolland W. Redlin, American lawyer and politician (d. 2011)
- 1924 – David Beattie, New Zealand judge and politician, 14th Governor-General of New Zealand (d. 2001)
- 1924 – Carlos Humberto Romero, Salvadoran politician, President of El Salvador
- 1924 – Al Rosen, American baseball player and manager (d. 2015)
- 1928 – Joss Ackland, English actor
- 1928 – Vance Haynes, American archaeologist, geologist, and author
- 1928 – Seymour Papert, South African mathematician and computer scientist, co-created the Logo programming language (d. 2016)
- 1932 – Jaguar, Brazilian cartoonist
- 1932 – Gene H. Golub, American mathematician and academic (d. 2007)
- 1932 – Masten Gregory, American race car driver (d. 1985)
- 1932 – Reri Grist, American soprano and actress
- 1936 – Jack R. Lousma, American colonel, astronaut, and politician
- 1936 – Henri Richard, Canadian ice hockey player
- 1936 – Alex Rocco, American actor (d. 2015)
- 1940 – Bartholomew I of Constantinople
- 1940 – William H. Turner, Jr. American horse trainer
- 1944 – Ene Ergma, Estonian physicist and politician
- 1944 – Dennis Farina, American police officer and actor (d. 2013)
- 1944 – Nicholas Frayling, English priest and academic
- 1944 – Phyllis Frelich, American actress (d. 2014)
- 1944 – Steve Mingori, American baseball player (d. 2008)
- 1944 – Paolo Eleuteri Serpieri, Italian author and illustrator
- 1948 – Hermione Lee, English author, critic, and academic
- 1948 – Patricia A. McKillip, American author
- 1948 – Henry Small, American-born Canadian singer
- 1952 – Sharon Dahlonega Raiford Bush, American journalist and producer
- 1952 – Tim Powers, American author and educator
- 1952 – Raisa Smetanina, Russian cross-country skier
- 1952 – Bart Stupak, American police officer and politician
- 1956 – Jonathan Coleman, English-Australian radio and television host
- 1956 – Bob Speller, Canadian businessman and politician, 30th Canadian Minister of Agriculture
- 1956 – Aileen Wuornos, American serial killer (d. 2002)
- 1960 – Khaled, Algerian singer-songwriter
- 1960 – Lucian Grainge, English businessman
- 1960 – Richard Ramirez, American serial killer (d. 2013)
- 1960 – Tony Robbins, American motivational speaker and author
- 1964 – Dave Brailsford, English cyclist and coach
- 1964 – Lyndon Byers, Canadian ice hockey player and radio host
- 1964 – Mervyn Warren, American tenor, composer, and producer
- 1968 – Suanne Braun, South African-English actress
- 1968 – Chucky Brown, American basketball player and coach
- 1968 – Pete Fenson, American curler and sportscaster
- 1968 – Naoko Iijima, Japanese actress and model
- 1968 – Bryce Paup, American football player and coach
- 1968 – Howard Tayler, American author and illustrator
- 1968 – Eugene Volokh, Ukrainian-American lawyer and educator
- 1968 – Frank Woodley, Australian actor, producer, and screenwriter
- 1972 – Mike Pollitt, English footballer and coach
- 1972 – Antonio Sabàto, Jr., Italian-American model and actor
- 1972 – Pedro Sánchez, Spanish politician
- 1972 – Dave Williams, American singer (d. 2002)
- 1972 – Saul Williams, American singer-songwriter
- 1972 – Pedro Zamora, Cuban-American activist and educator (d. 1994)
- 1976 – Zoë Baker, English-New Zealand swimmer and coach
- 1976 – Terrence Long, American baseball player
- 1976 – Ja Rule, American rapper and actor
- 1980 – Çağdaş Atan, Turkish footballer
- 1980 – Chris Conley, American singer-songwriter and guitarist
- 1980 – Patrick Côté, Canadian mixed martial artist
- 1980 – Simon Gagné, Canadian ice hockey player
- 1980 – Rubén Plaza, Spanish cyclist
- 1980 – Clinton Toopi, New Zealand rugby player
- 1980 – Taylor Twellman, American soccer player and sportscaster
- 1984 – Darren Ambrose, English footballer
- 1984 – Rica Imai, Japanese model and actress
- 1984 – Cullen Jones, American swimmer
- 1984 – Nuria Martínez, Spanish basketball player
- 1984 – Adam Sinclair, Indian field hockey player
- 1984 – Rakhee Thakrar, English actress
- 1984 – Dennis Walger, German rugby player
- 1984 – Cam Ward, Canadian ice hockey player
- 1988 – Lena Gercke, German model and television host
- 1988 – Scott Golbourne, English footballer
- 1988 – Benedikt Höwedes, German footballer
- 1988 – Brent Macaffer, Australian Rules footballer
- 1988 – Bobby Sanguinetti, American ice hockey player
- 1992 – Sean Abbott, Australian cricketer
- 1992 – Perry Kitchen, American soccer player
- 1992 – Caitlin EJ Meyer, American actress
- 1992 – Saphir Taïder, French-Algerian footballer
- 1996 – Claudia Williams, New Zealand tennis player
- 992 – Oswald of Worcester, French archbishop and saint (b. 925)
- 1212 – Hōnen, Japanese monk, founded Jōdo-shū (b. 1133)
- 1528 – Patrick Hamilton, Scottish martyr and reformer (b. 1504)
- 1592 – Alessandro Striggio, Italian composer and diplomat (b. 1540)
- 1600 – Caspar Hennenberger, German pastor, historian, and cartographer (b. 1529)
- 1604 – John Whitgift, English archbishop and academic (b. 1530)
- 1740 – Pietro Ottoboni, Italian cardinal (b. 1667)
- 1744 – John Theophilus Desaguliers, French-English physicist and philosopher (b. 1683)
- 1792 – Johann Andreas Stein, German piano builder (b. 1728)
- 1820 – Johann Joachim Eschenburg, German historian and critic (b. 1743)
- 1848 – Louis-François Lejeune, French general, painter, and lithographer (b. 1775)
- 1852 – Matsudaira Katataka, Japanese daimyo (b. 1806)
- 1868 – Ludwig I of Bavaria (b. 1786)
- 1880 – James Milne Wilson, Scottish-Australian soldier and politician, 8th Premier of Tasmania (b. 1812)
- 1908 – Pat Garrett, American sheriff (b. 1850)
- 1908 – John Hope, 1st Marquess of Linlithgow, Scottish-Australian politician, 1st Governor-General of Australia (b. 1860)
- 1920 – Ernie Courtney, American baseball player (b. 1875)
- 1928 – Adolphe Appia, Swiss architect and theorist (b. 1862)
- 1928 – Ina Coolbrith, American poet and librarian (b. 1841)
- 1940 – E. F. Benson, English archaeologist and author (b. 1867)
- 1944 – Pehr Evind Svinhufvud, Finnish lawyer, judge, and politician, 3rd President of Finland (b. 1861)
- 1948 – Robert Barrington-Ward, English lawyer and journalist (b. 1891)
- 1948 – Rebel Oakes, American baseball player and manager (b. 1883)
- 1952 – Quo Tai-chi, Chinese politician and diplomat, Permanent Representative of China to the United Nations (b. 1888)
- 1956 – Elpidio Quirino, Filipino lawyer and politician, 6th President of the Philippines (b. 1890)
- 1960 – Melvin Purvis, American police officer and FBI agent (b. 1903)
- 1960 – Walter Yust, American journalist and author (b. 1894)
- 1964 – Frank Albertson, American actor and singer (b. 1909)
- 1968 – Lena Blackburne, American baseball player, coach, and manager (b. 1886)
- 1968 – Tore Ørjasæter, Norwegian poet and educator (b. 1886)
- 1972 – Tom Davies, American football player and coach (b. 1896)
- 1976 – Florence P. Dwyer, American politician (b. 1902)
- 1980 – Yigal Allon, Israeli general and politician, Prime Minister of Israel (b. 1918)
- 1980 – Gil Elvgren, American painter and illustrator (b. 1914)
- 1984 – Ludwik Starski, Polish screenwriter and songwriter (b. 1903)
- 1988 – Sidney Harmon, American screenwriter and producer (b. 1907)
- 1992 – Ruth Pitter, English poet and author (b. 1897)
- 1996 – Wes Farrell, American singer-songwriter and producer (b. 1939)
- 1996 – Ralph Rowe, American baseball player, coach, and manager (b. 1924)
- 2000 – Dennis Danell, American guitarist (b. 1961)
- 2004 – Kagamisato Kiyoji, Japanese sumo wrestler, the 42nd Yokozuna (b. 1923)
- 2004 – Jerome Lawrence, American playwright and author (b. 1915)
- 2004 – Harold Bernard St. John, Barbadian lawyer and politician, 3rd Prime Minister of Barbados (b. 1931)
- 2004 – Lorrie Wilmot, South African cricketer (b. 1943)
- 2008 – Janet Kagan, American author (b. 1946)
- 2008 – Erik Ortvad, Danish painter and illustrator (b. 1917)
- 2008 – Akira Yamada, Japanese scholar and philosopher (b. 1922)
- 2012 – Roland Bautista, American guitarist (b. 1951)
- 2012 – Davy Jones, English singer, guitarist, and actor (b. 1945)
- 2012 – Sheldon Moldoff, American illustrator (b. 1920)
- 2012 – P. K. Narayana Panicker, Indian social leader (b. 1930)
- 2016 – Wenn V. Deramas, Filipino director and screenwriter (b. 1968)
- 2016 – Gil Hill, American police officer, actor, and politician (b. 1931)
- 2016 – Josefin Nilsson, Swedish singer (b. 1969)
- 2016 – Louise Rennison, English author (b. 1951)
Holidays and observances
- Christian feast day:
- The fourth day of Ayyám-i-Há (Bahá'í Faith) (Please note that this observance is only locked into this date the Gregorian calendar on this date if Bahá'í Naw-Rúz takes place on March 21, which it doesn't in all years)
- Rare Disease Day (in leap years, otherwise is February 28th)
- Bachelor's Day (Ireland, United Kingdom)
- In Discordianism, Feburary 29 is coterminus with St. Tibs' day in the Discordian calendar
There is a popular tradition known as Bachelor's Day in some countries allowing a woman to propose marriage to a man on February 29. If the man refuses, he then is obliged to give the woman money or buy her a dress. In upper-class societies in Europe, if the man refuses marriage, he then must purchase 12 pairs of gloves for the woman, suggesting that the gloves are to hide the woman's embarrassment of not having an engagement ring. In Ireland, the tradition is supposed to originate from a deal that Saint Bridget struck with Saint Patrick.
- Lerner, Ed. K. Lee; Lerner, Brenda W. (2004). "Calendar". The Gale Encyclopedia of Science. Detroit, MI: Gale. pp. 679–82.
- "Calendar Reform". The Catholic Encyclopedia. Retrieved 5 May 2016.
- Censorinus, The Natal Day, 20.28, tr. William Maude, New York 1900, available at .
- Bonnie Blackburn and Leofranc Holford-Strevens, The Oxford companion to the year (Oxford: Oxford University Press, 1999) 678–680.
- Leigh, Rob. "Leap year February 29: 29 things you need to know about leap years and their extra day". Mirror Online. Retrieved 1 March 2016.
- "Part B – Entitlement to register" (PDF). The Electoral Commission. February 2008. Retrieved February 6, 2012.
- "Cap 410, s.5 Chapter 410: Age of Majority (Related Provisions) Ordinance". Department of Justice. The Government of the Hong Kong Special Administrative Region of the People's Republic of China. June 30, 1997.
- "Land Transport (Driver Licensing) Rule 1999 § 2(2)". Parliamentary Counsel Office. December 1, 2014. Retrieved June 11, 2013.
- Re an Infant (1936) 31 MCR 42
- Article 121 of the Civil Code Part I General Principles of the Republic of China in effect in Taiwan.
- "Leap day not a significant concern in field of law, government". University of Iowa News Service. The University of Iowa. February 27, 2012. Retrieved October 7, 2013.
- Sullivan, Arthur; Gilbert, W.S. (August 20, 2011). "The Pirates of Penzance". Gilbert and Sullivan Archive. Retrieved February 6, 2012.
- ""'Excuse Me, But I Think You're Sitting on My Hershey Bar' and Other Openers", The Washington Post, February 29, 1980. p. D5
- Oblander, Terry. "Leap Year: It Depends on How You Figure It". Akron Beacon Journal. February 29, 1988.
- "Leap Day customs & traditions". Time and Date AS. Retrieved October 2, 2014.
- Tan, Tiffany. "'Will you marry me?' she says", ChinaDaily.com.cn, February 29, 2012.
- "A Convenient Year for a Leap". Wisconsin State Journal (Madison, Wisconsin). February 28, 1992. "Tradition dies hard in Aurora , Ill., where every Feb. 29 single women are deputized and allowed to arrest bachelors and fine them $4."
- Krucoff, Carol. "By Leaps and Seconds: It's Feb. 29: Call It a Time-Consuming Day", The Washington Post. February 29, 1984, p. F9. "Leap Day was not created, as rumor has it, to give women one day out of 1,461 to chase men (who needs a special day for that?)—even though the town of Aurora, Ill., deputizes single women and allows them to arrest bachelors (fine, $4) every Feb. 29."
- Mudhar, Raju (February 29, 2012). "Leap Day 2012: What you need to know". The Star.
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