Eufrosina Dvoichenko-Markov (1901–1980, Moscow, Russia) was a Russian-American history and literary scholar identified by NSA as agent Masha who worked for the New York NKGB Rezidentura from 1943 to 1945. Her son, Sgt. Demetrius Dvoichenko-Markov of the United States Army, is also identified by Venona papers as a Soviet agent, but spent the rest of his life as an academician in the USA. Masha provided Soviet intelligence with information on Romanians, Carpatho-Russians and other exile groups in the United States. Masha also provided information on United States Department of State personnel with whom she had contact.
- Eufrosina Dvoichenko-Markov, Jefferson and the Russian Decembrists, American Slavic and East European Review, Vol. 9, No. 3. (Oct., 1950), pp. 162–168. JSTOR link
- Eufrosina Dvoichenko-Markov, The Pulkovo Observatory and Some American Astronomers of the Mid-19th Century, Isis, Vol. 43, No. 3. (Sep., 1952), pp. 243–246. JSTOR link
- John Earl Haynes and Harvey Klehr, Venona: Decoding Soviet Espionage in America, Yale University Press (1999), pg. 259, 347, 449. ISBN 0-300-07771-8.
- John Earl Haynes, "Cover Name, Cryptonym, CPUSA Party Name, Pseudonym, and Real Name Index. A Research Historian’s Working Reference" (revised February 2007), on the author's web site.