||This article has multiple issues. Please help improve it or discuss these issues on the talk page.
The 1990s X-Factor team.
Art by Joe Quesada.
|Group publication information|
|First appearance||(1980s team)
X-Factor #1 (February 1986)
X-Factor #71 (October 1991)
|Created by||1980s team:
|Type of organization||Team|
The Pentagon, Washington, D.C., Fall's Edge, Virginia
Marvel Girl (Jean Grey)
|See: List of X-Factor members|
|Cover to X-Factor #1.
Art by Jackson Guice.
|Series publication information|
|Format||(vols. 3 [reverted to 1])
(vol. 1 & 2)
|Publication date||(vol. 1)
February 1986 – September 1998
June – October 2002
February 2006 – Present
|Number of issues||(vol. 1)
94 (as of September 2012)
|Essential X-Factor: Volume 1||ISBN 0-7851-1886-1|
|Essential X-Factor: Volume 2||ISBN 0-7851-2099-8|
|The Longest Night||ISBN 0-7851-1817-9|
|Life & Death Matters||ISBN 0-7851-2146-3|
|Many Lives of Madrox||ISBN 0-7851-2359-8|
X-Factor is an American comic book series published by Marvel Comics. It is a spin-off from the popular X-Men franchise, featuring characters from X-Men stories. The series has been relaunched several times with different team rosters, most recently in X-Factor v. 3 as X-Factor Investigations.
X-Factor launched in 1986, featuring an eponymous team composed of the five original X-Men. In 1991, the founding members were incorporated back into the regular X-Men series, and X-Factor relaunched as a U.S. government-sponsored team incorporating many secondary characters from the X-Men mythos. The series was canceled in 1998.
In 2002, a four-part X-Factor mini-series detailed an investigation by the Mutant Civil Rights Task Force into an alleged conspiracy by hate-groups to commit murder against mutants. The series was written by Jeff Jensen with artwork by Arthur Ranson.
In 2005, a new X-Factor series was launched, following the mutant detective agency X-Factor Investigations. Written by Peter David, the series drew acclaim from Ain't It Cool News, as well as controversy for establishing a romantic relationship between Rictor and Shatterstar, a move criticized by Shatterstar's co-creator, Rob Liefeld. The series also won a 2011 GLAAD Media Award for Outstanding Comic Book.
Publication history 
Volume 1 (1986–1998) 
Original team (1986-1991) 
X-Factor launched in 1986 featuring an eponymous team composed of the five original X-Men that debuted in X-Men #1 (1963):
- Angel - A millionaire heir, capable of flight by means of two feathery wings extending from his back.
- Beast - A brilliant scientist possessing bestial strength and agility.
- Cyclops - Former X-Men team leader, with the ability to emit powerful "optic blasts" from his eyes.
- Jean Grey (Marvel Girl) - Cyclops’ long-time love, possessing telekinetic abilities.
- Iceman - A brash jokester, gifted with cryokinetic abilities.
The founding of X-Factor hinged upon the reunion of the original X-Men, an event complicated by the extensive histories of the characters following the initiation of a new team of X-Men in 1975.
In the 1970s and early 1980s, Angel, Beast, and Iceman wandered through various superhero teams. By 1985, all three were members of the Defenders, whose monthly series was shortly canceled, which freed the trio.[clarification needed]
The returns of Cyclops and Jean Grey were more difficult. In the late 1970s, Jean Grey was killed during the seminal Dark Phoenix Saga, and was not originally conceived in the team's female role, with fellow mutant Dazzler as the front-runner for that part. However, writer Kurt Busiek suggested a way to add Jean Grey to the roster that became one of the most significant cases of retconning in comic book history: Jean Grey had never actually been the Phoenix. Instead, the Phoenix entity copied Grey's identity and form, keeping her safe in a cocoon-like structure beneath Jamaica Bay. Busiek related the idea to Roger Stern, who related it to John Byrne. Byrne wrote and illustrated Fantastic Four #286 (1985), incorporating Busiek's idea.
In order to join the team, Cyclops walked out on his new wife Madelyne Pryor, an Alaskan pilot who bore a strange resemblance to Grey, and their infant son, Nathan Christopher. These events, along with the resurrection of Grey in general, were highly controversial with fans.
The original X-Men disassociated with the current team because Professor X had placed their old nemesis, Magneto, as its leader. The five set up a business advertised as mutant-hunters for hire, headquartered in the TriBeCa neighborhood of downtown New York City, posing as "normal" (non-superpowered) humans to their clients. The mutants X-Factor captured were secretly trained to control their powers and reintegrated into society. Through their "mutant hunting" they recruited a group of young wards:
- Artie Maddicks - A pink-skinned, mute child who could project hologram-like images of his thoughts.
- Tabitha Smith - A young woman who ran away from her abusive father, who can create handheld energy spheres that she can explode at will, which she calls "time bombs".
- Rusty Collins - A former member of the U.S. Navy whose pyrokinesis first manifested uncontrollably, severely injuring a woman.
- Leech - A green-skinned young boy, who can dampen the mutant powers of those around him.
- Rictor - A Mexican teenager who can produce powerful seismic waves.
- Skids - A runaway who could project a protective force field around her body.
The team would also go into action in costume, posing as mutant outlaws known as the "X-Terminators." Eventually, the team decided that the "mutant hunter" ruse did more harm than good by inflaming hatred. Not only was the concept rejected, but it was blamed on X-Factor's original business manager, Cameron Hodge, who was revealed as a mutant-hating mastermind.
Bob Layton and Jackson Guice wrote and illustrated, respectively, the first few issues of X-Factor. They soon turned over creative duties to married collaborators Louise Simonson (writer) and Walt Simonson (artist). Louise introduced, in X-Factor #6 (1986), Apocalypse, who would appear in multiple issues and become X-Factor's arch-nemesis. The Simonsons placed the series in line with the darker tone of most X-books. In X-Factor #10, the Marauders, a group of savage mutant mercenaries, severely injured Angel's wings, which were later amputated. Despondent, Angel attempted suicide by detonating his airliner mid-flight, but Apocalypse rescued him from the wreckage and transformed him into Death, one of his Four Horsemen. Death was a fearsome creature that possessed metal wings and blue skin. Angel escaped Apocalypse's control, but the physical changes to his body remained. He became known as Archangel and became a much darker character, eventually rejoining team in issue #36. Angel's replacement on X-Factor, Caliban, turned to Apocalypse for more power in issue #24, with Apocalypse leaving X-Factor his ship in return.
In the 1989 crossover Inferno, Madelyne Pryor was revealed to be a clone of Jean Grey created by the nefarious mutant geneticist Mister Sinister. Demons had used Madelyne's pain at Scott's rejection of her to manipulate her into becoming the Goblyn Queen. Madelyne planned to sacrifice Nathan to open an interdimensional portal and to hurt Cyclops and Sinister as much as possible. X-Factor teamed up with the X-Men to rescue Nathan, bridging the gap between the two teams. Madelyne suffered a mental breakdown upon discovering she was a clone and killed herself.
During Inferno, X-Factor's teenage wards, along with a young paraplegic mutant named Taki Matsuya, starred in the X-Terminators miniseries and shortly after folded into the X-Men's junior team, the New Mutants.
In the last major storyline of the first X-Factor series, published in early 1991, Apocalypse kidnapped Nathan Summers, sensing that he would grow up to be a powerful mutant and possible threat. X-Factor rescued Nathan from Apocalypse's lunar base, but found him infected with a "techno-organic" virus that could not be treated in the present time. A clan of rebels from the future, known as the Askani, sent a representative to the present time to bring Nathan 2,000 years into the future to be treated. Fully grown, he would return to the 20th century as the antihero, Cable.
Shortly after this, the X-Factor, the X-Men, and several minor characters teamed up to fight the telepathic Shadow King in another crossover event, The Muir Island Saga. Afterward, the original members of X-Factor rejoined the X-Men and several minor characters from various X-Men-related series became founding members of the all-new X-Factor.
The era of the original X-Factor had lasting effects on the X-Men mythos. It introduced Apocalypse and the Archangel version of Angel and explained the connection between Apocalypse, Cable, Cyclops, Jean Grey, Pryor, and Sinister. All of these elements continued in future X-Men series.
Government team (1991-1998) 
Rather than end the series, Marvel hired writer Peter David and illustrator Larry Stroman to recreate X-Factor with new members, all of whom were already allies of the X-Men, and three of whom were involved in the Muir Island Saga. The new X-Factor worked for the Pentagon making them the only salaried mutant team. Their relationship with their benefactors was often strained and complicated. The new X-Factor, debuting in issue #71, included:
- Valerie Cooper - A U.S. government agent with history as both ally and adversary of the X-Men who became X-Factor's government liaison, carrying over from her duties as liaison to a prior government-sponsored team of mutants, Freedom Force.
- Havok - A former X-Man and brother of Cyclops who could manipulate powerful, but hard to control, cosmic rays. Havok served as X-Factor's leader.
- Multiple Man - He could create duplicates of himself on physical impact. He was previously offered X-Men membership, but he declined, opting instead to work at the Muir Island research centre.
- Polaris - Havok's long-time lover and also a former X-Man who could control magnetism.
- Quicksilver - A long-running Avengers character and former foe of the X-Men, who possessed super speed and a difficult temperament. He was a late addition to the team roster.
- Strong Guy AKA Guido - A wise-cracking character who could rechannel kinetic energy aimed at him, transforming it into muscular mass and power. Lila Cheney's former bodyguard.
- Wolfsbane - A Scottish, former New Mutant who could transform into a wolf-like creature. Some artificial manipulation of her feelings caused her to love Havok, much against her will, and caused her much conflict and frustration because she knew he loved Polaris.
Although X-Factor was not as flashy or wildly popular as other X-books, David was applauded for his use of humor and cultural references, and his ability to flesh out characters that had previously only been background characters.
David left in 1993. The series continued under writer J. M. DeMatteis and artist Jan Duursema, but struggled to distinguish itself among other X-books. Shortly after David's tenure on the book ended, Forge, a former government weapons contractor whose mutant powers were his brilliant engineering skills, was added to the group; first replacing Cooper as their liaison after she had been compromised by one of Magneto's Acolytes, and later as an active member. Cooper later became an active member as well, her marksmanship and athletic skills compensating for her lack of superhuman powers.
By 1995, Multiple Man had apparently died of the Legacy Virus, a deadly illness that attacked mutant genes, which was later revealed to have only killed one of his duplicates. Strong Guy was put into suspended animation after suffering a heart attack caused by the stress his extra mass put on his body. Wolfsbane, who had been cured of her artificial love for Alex, transferred to the European mutant team Excalibur. Havok left to infiltrate a mutant terrorist ring.
- Mystique - A shapeshifting mutant criminal and master of espionage. Mystique was forced to join X-Factor following her capture by federal agents.
- Sabretooth - A homicidal mutant criminal who possessed talons, heightened senses, and a healing factor. Like Mystique, Sabretooth was a captive member that Forge used special technology to control.
- Shard - A holographic computer program that took on the personality of the X-Man Bishop's deceased sister of the same name. Bishop was a time-traveler from a distant future, where he and Shard were members the X-Men descendants, Xavier's Security Enforcers. The holographic Shard was brought to the 20th century with Bishop.
- Wild Child - Former member of Alpha Flight who possessed heightened senses, fangs, and claws.
Afterward, writer Howard Mackie injected more political and espionage elements into the series, a trend that culminated in the team's secession from government sponsorship. Multiple Man and Strong Guy appeared again at the same time. Despite Forge managing to fix Strong Guy's problems, he did not rejoin the team. The popularity of X-Factor continued to dwindle and Mystique and Sabretooth, two popular X-Men villains, failed to draw in more readers. Wild Child mutated out of control, Mystique hunted down Sabretooth (who had kidnapped young Tyler Trevor Chase), and Forge wanted nothing to do with X-Factor.
In 1997, Marvel attempted yet another revival. After various stories focusing on individual characters, a new team was gathered consisting of Havok, Multiple Man, Polaris, Shard, and other members of the X.S.E. (Fixx, and Greystone) that were brought to the 20th century (their teammate Archer, who also came back in time, turned down an offer to join)). However, this version of the team was disbanded in the same issue in which they debuted. In that issue, #149 (1998), Greystone built a time machine meant to take him and his compatriots back to the future. However, the device exploded, killing Greystone and, apparently, Havok. Afterward, X-Factor disbanded.
In fact, the time machine transported Havok to a parallel world, populated by twisted versions of Marvel characters. He explored this strange world in the series Mutant X, which lasted from 1998 until 2001. Although Marvel planned to revive X-Factor as an ongoing title after Mutant X ended, this did not happen for another 4 years.
Volume 2 (2002 miniseries) 
A four-issue X-Factor limited series was launched in 2002. This series focused on the government's new Mutant Civil Rights Task Force, humans who investigated anti-mutant hate crimes and inadvertently discovered an anti-mutant conspiracy within their own ranks. This series focused heavily on the "mutants as a metaphor for minorities" aspects of the X-Men concept.
Volume 3 (2005–present) 
X-Factor Investigations is a detective agency run by Jamie Madrox, formerly known as Multiple Man. The agency was originally named "XXX Investigations," but team members thought that sounded too much like Madrox was investigating pornography. The new name is taken from the government-sponsored group the three founders had previously served on.
The initial staff consisted of Madrox's best friend and special enforcer, Guido Carosella (Strong Guy), and former teammate Rahne Sinclair (Wolfsbane). Following the House of M, Madrox's newfound wealth from winning a Who Wants to Be a Millionaire?-style game show allowed him to recruit several of his former colleagues from the Paris branch of the now defunct X-Corporation. New members include M (Monet), a powerless Rictor, Siryn, and Layla Miller, who has inserted herself into the group to keep them from discovering the truth behind the mutant Decimation event.
An eighth member was acquired temporarily a little later in 2007, when Monet rescued (or abducted, depending on your viewpoint) a French orphan girl named Nicole with the reluctant help of Siryn and the clandestine help of a mysterious hooded personage of great power, and took her back to America. Nicole was supposedly the orphaned daughter of ex-mutants lynched by a mob. Monet felt personally responsible for Nicole because she had tried, but failed, to prevent the pogrom. Nicole, in an attempt to kill Layla, is later revealed as a robot and hit by a train. Nicole's cover story was a complete fabrication. She had been manufactured as a tool to destroy X-Factor.
Peter David has put a noir spin on the mutant series and has dealt with the former Multiple Man, Jamie Madrox, as the central character. The new series spins directly out of House of M and opens with a suicide attempt by Rictor, who has lost his powers in the Decimation that has caused 90-percent of all mutants to lose their powers. The series deals with the group's attempt to unravel the truth behind the Decimation and its aftermath, getting involved with the events of Marvel's crossover Civil War, fighting with Singularity Investigations, and dealing with Madrox's powers and their consequences. The team also attempted to protect Professor Xavier when the Hulk attacked him and the New X-Men in the World War Hulk crossover.
During the Messiah Complex crossover, Jamie and Layla travel to a dystopian future in which mutants are persecuted and imprisoned. Jamie manages to escape and return to the early 21st century, but Layla is still trapped in that undesirable future. Rahne believes she knows that Layla will return and will marry Jamie when she grows up. However, Rahne fears (because of a glimpse she has had of the future) that she, while in her wolf shape, will murder both Jamie and Layla. To prevent this, she quits the team and joins X-Force. Rictor also quits, reducing the team to only four members. They are attacked by the Isolationist, a villain with a plan to kill all mutants, but defeat him with the unintended help of Pietro Maximoff.
In the first half of 2009, Jamie travels to the future with the help of an aged Layla Miller and helps the Summers' rebellion, led by a cyborg Scott Summers and his daughter Ruby, while the rest of the team is in the present. After battling Arcade, who captured Rictor (who then rejoins), the team is joined by the real Longshot and Darwin and meets one of Jamie's duplicates, who calls himself Cortex.
Writer Peter David's decision to explicitly establish male characters Shatterstar and Rictor entering a romantic relationship in X-Factor #45 (August 2009) — confirming clues that had been established in X-Force years earlier — drew criticism from Shatterstar's co-creator, Rob Liefeld, though Editor-in-Chief Joe Quesada supported David's story. David would eventually be nominated for and win a 2011 GLAAD Media Award for Outstanding Comic Book for this second run on the title.
In December 2009, the series resumed its original numbering with issue #200, with 149 issues of the first volume plus 50 issues of the third volume constituting the previous 199 issues.
Collected editions 
Volume 1 
|Title||Material collected||Publication date||ISBN|
|Essential X-Factor Vol. 1||X-Factor #1-16, Annual #1; The Mighty Thor #373-374; Power Pack #27 (b&w)||November 2005||0-7851-1886-1|
|Essential X-Factor Vol. 2||X-Factor #17-35, Annual #2 (b&w)||January 2007||0-7851-2099-8|
|Essential X-Factor Vol. 3||X-Factor #36-50||December 2009||0-7851-3078-0|
|Essential X-Factor vol. 4||X-Factor #51-59, Annual #4-5; X-Factor: Prisoner of Love; Marvel Fanfare #50; material from Fantastic Four Annual # 23, New Mutants Annual #6, Uncanny X-Men Annual #14||February 2012||978-0785162858|
|Essential X-Factor vol. 5||X-Factor #60-70, Annual #6; Uncanny X-Men #270-272, 280; material from Uncanny X-Men Annual #15, New Mutants #95-97, material from New Mutants Annual #7||Dcecember 2012||978-0785163534|
|X-Men: Phoenix Rising||Avengers #263; Fantastic Four #286; X-Factor #1; and Classic X-Men #8 and #43||June 2009||0-7851-3948-6|
|X-Men: Mutant Massacre||X-Factor #9-11; Uncanny X-Men #210-213; New Mutants #46; Thor #373-374; Power Pack #27||October 2001||0-7851-0224-8|
|X-Men: Mutations||X-Factor #15, 24-25; Amazing Adventures vol. 2, #11, 17; Uncanny X-Men #256-258||October 1996||0-7851-0197-7|
|X-Men: The Fall of the Mutants||X-Factor #24-26; Uncanny X-Men #224-226; New Mutants #59-61||February 2002||0-7851-0825-4|
|X-Men: Inferno (Hardcover)||X-Factor #33-40; Uncanny X-Men #239-243; X-Terminators #1-4; New Mutants #71-73; X-Factor Annual #4||June 2009||978-0785137771|
|X-Men: Inferno||X-Factor #36-39; Uncanny X-Men #239-243; New Mutants #71-73||December 1996||0-7851-0222-1|
|Acts of Vengeance Crossovers Omnibus||X-Factor #49-50; Wolverine (1988) #19-20; Uncanny X-Men #256-258; Fantastic Four (1961) #334-336; Dr. Strange, Sorcerer Supreme (1988) #11-13; Incredible Hulk (1968) #363; Punisher (1987) #28-29; Punisher War Journal (1988) #12-13; Marc Spector: Moon Knight (1989) #8-10; Daredevil (1964) #275-276; Power Pack (1984) #53; Alpha Flight (1983) #79-80; New Mutants (1983) #84-86; Damage Control (1989) #1-4; and Web of Spider-Man #64-65||August 2011||978-0-7851-4488-5|
|X-Men: X-Tinction Agenda||X-Factor #60-62; Uncanny X-Men #270-272; New Mutants #95-97||December 1998||0-7851-0053-9|
|X-Men: X-Tinction||X-Factor #60-62; Uncanny X-Men #235-238 & #270-272; New Mutants (1983) #94-96||August 2011||978-0785155317|
|X-Men by Chris Claremont and Jim Lee Vol. 2||X-Factor #63-70; Uncanny X-Men #273-280; X-Men (1991) #1-9 + material from #10-11; Ghost Rider (1990) #26-27||January 2012||978-0785159056|
|X-Factor: Visionaries Peter David Vol. 1||X-Factor #71-75||December 2005||0-7851-1872-1|
|X-Factor: Visionaries Peter David Vol. 2||X-Factor #76-78; Incredible Hulk #390-392||March 2007||0-7851-2456-X|
|X-Factor: Visionaries Peter David Vol. 3||X-Factor #79-83, Annual #7||October 2007||0-7851-2457-8|
|X-Factor: Visionaries Peter David Vol. 4||X-Factor #84-89, Annual #8||June 2008||0-7851-2745-3|
|X-Men: X-Cutioner's Song||X-Factor #84-86; Uncanny X-Men #294-296; X-Men #14-16; X-Force #16-18||May 1994||0-7851-0025-3|
|X-Men: Fatal Attractions||X-Factor #92; X-Force #25; Uncanny X-Men #304; X-Men #25; Wolverine #75; Excalibur #71||August 2000||0-7851-0748-7|
|The Origin of Generation X: Tales of the Phalanx Covenant||X-Factor #106; Uncanny X-Men #316-317; X-Men vol. 2, #36-37; X-Force #38; Excalibur #82; Wolverine vol. 2, #85; Cable #16; Generation X #1||June 2001||0-7851-0216-7|
|X-Men: Legion Quest||X-Factor #109; Uncanny X-Men #320-321; X-Men vol. 2, #40-41||March 1996||0-7851-0179-9|
|X-Men: Prelude to the Age of Apocalypse||X-Factor #108-109; Uncanny X-Men #319-321; X-Men (vol. 2) #38-41; Cable #20; X-Men: Age of Apocalypse Ashcan Edition||May 2011||978-0-7851-5508-9|
|X-Men: The Complete Onslaught Epic Vol. 2||X-Factor #125-126; Excalibur #100; Fantastic Four #415; Amazing Spider-Man #415; Sensational Spider-Man #8; Spider-Man #72; Green Goblin #12; Punisher #11; Wolverine #104; X-Man #17; X-Men #55; Uncanny X-Men #336; X-Force #58||June 2008||0-7851-2824-7|
Volume 3 
|Title||Material collected||Publication date||ISBN|
|Madrox: Multiple Choice||Madrox #1-5 (prelude to X-Factor vol. 3)||April 2005||0-7851-1500-5|
|X-Factor: The Longest Night||X-Factor vol. 3, #1-6||March 2007||0-7851-1817-9|
|X-Factor: Life and Death Matters||X-Factor vol. 3, #7-12||February 2007||0-7851-2146-3|
|X-Factor: Many Lives of Madrox||X-Factor vol. 3, #13-17||November 2007||0-7851-2359-8|
|X-Factor: Heart of Ice||X-Factor vol. 3, #18-24||April 2008||0-7851-2360-1|
|X-Men: Messiah Complex||X-Factor vol. 3, #25-27; Uncanny X-Men #492-494; X-Men #205-207; New X-Men #44-46; X-Men: Messiah Complex - Mutant Files||November 2008||0-7851-2320-2|
|X-Factor: The Only Game in Town||X-Factor vol. 3, #28-32; X-Factor: The Quick and the Dead||January 2009||0-7851-2863-8|
|X-Factor: Secret Invasion||X-Factor vol. 3, #33-38; She-Hulk vol. 2, #31||June 2009||0-7851-2865-4|
|X-Factor: Time and a Half||X-Factor vol. 3, #39-45||December 2009||0-7851-3836-6|
|X-Factor: Overtime||X-Factor vol. 3, #46-50; X-Factor: Layla Miller||December 2009||0-7851-3837-4|
|X-Factor: The Invisible Woman Has Vanished||X-Factor #200-203||June 2010||0-7851-4657-5|
|X-Factor: Second Coming||X-Factor #204-206; Nation X: X Factor||September 2010||0-7851-4892-0|
|X-Factor: Happenings in Vegas||X-Factor #207-212||March 2011||0-7851-4658-X|
|X-Factor: Scar Tissue||X-Factor #213-219||June 2011||0-7851-5283-0|
|X-Factor: Hard Labor||X-Factor #220-224||November 2011||0-7851-5285-7|
|X-Factor: Super Unnatural||X-Factor #224.1, 225-228||February 2012||0-7851-6058-2|
|X-Factor: They Keep Killing Jamie Madrox||X-Factor #229-232||June 2012||0-7851-6060-4|
|X-Factor: Together Again for the First Time||X-Factor #233-236||November 2012||0-7851-6063-9|
|X-Factor: The Road to Redemption||X-Factor #237-240||December 2012||0-7851-6413-8|
|X-Factor: Breaking Points||X-Factor #241-245||March 2013||0-7851-6512-6|
|X-Factor: Short Stories||X-Factor #246-249||March 2013||0-7851-6699-8|
Other versions 
Ultimate Marvel 
In other media 
- X-Factor appeared in the X-Men episode "Cold Comfort". Its lineup consisted of Forge, Polaris, Multiple Man, Strong Guy, Quicksilver, Havok, and Wolfsbane. Iceman broke into their facility to find his girlfriend Polaris and ran afoul of the X-Men. When it came to a battle against the X-Factor, Forge said it was to test them. In "Family Ties," Quicksilver was again seen as a member of X-Factor and in "The Phalanx Covenant Part 1 & 2" Quicksilver, Forge and Polaris appear as members of X-Factor.
- "Comic Book Urban Legends Revealed #161". Comic Book Resources. June 26, 2008.
- "Comics of 1986 #30 X-Factor". Revolution Science Fiction. September 12, 2006.
- Sanderson, Peter (2007). The Marvel Comics Guide to New York City. New York City: Pocket Books. p. 11. ISBN 1-4165-3141-6.
- In issues such as X-Force #25, 34, 43, 49, 56, and X-Force '99 Annual.
- Melrose, Kevin (July 3, 2009). "Liefeld 'can't wait to someday undo' Shatterstar development". Comic Book Resources. Retrieved 2009-09-10.
- Quesada, Joe; Kiel Phegley (July 14, 2009). "Cup O' Joe: Thor, X-Factor, Punisher Max". Comic Book Resources. Retrieved 2009-09-10.
- "2011 GLAAD Media Awards Nominees". GLAAD.org. Retrieved 2011-01-20.
- "2011 http://www.glaad.org/releases/032011mediaawards". GLAAD.org. Retrieved 2011-03-20.
- Sunu, Steve (August 29, 2009). "Fan Expo: X-Factor Turns 200". Comic Book Resources.
- Brady, Matt (August 22, 2005). "X-ploring the X-Factor with Peter David". Newsarama.
- X-Factor issues on Marvel.com
- X-Factor, X-Factor vol. 2, and X-Factor vol. 3 at the Comic Book DB
- X-Factor, X-Factor vol. 2, and X-Factor vol. 3 at the Grand Comics Database
- X-Factor, X-Factor vol. 2, and X-Factor vol. 3 at UncannyX-men.net