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Gwertzman, Bernard (July 2, 1971). "Russians Mourn Soyuz 11 Astronauts". The New York Times. p.14; Teitel, Amy Shira (August 20, 2017). "Only Three People Have Died in Space". Discover Magazine. Archived from the original on July 2, 2020. Retrieved June 30, 2020.
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Revue Bulgare D'histoire. Publishing House of the Bulgarian Academy of Sciences. 1986. p.68. Archived from the original on 2020-09-26. Retrieved 2019-06-30.
Gwertzman, Bernard (July 2, 1971). "Russians Mourn Soyuz 11 Astronauts". The New York Times. p.14; Teitel, Amy Shira (August 20, 2017). "Only Three People Have Died in Space". Discover Magazine. Archived from the original on July 2, 2020. Retrieved June 30, 2020.
CM, Goodall; P, Shubik; JH, Weisburger (1966). "Dr. Franz David Bielschowsky: 1902-1965. An appreciation". Cancer Research. 26 (2). Cancer Res: 347–348. ISSN0008-5472. PMID5323326.