Haber, Fritz; Haber, Heinz (1950). "Possible methods of producing the gravity-free state for medical research". Journal of Aviation Medicine. 21 (5): 395–400. PMID14778792. Summary of the article: Campbell, Mark R. (2009). "Classics in space medicine. Possible methods of producing the gravity-free state for medical research". Aviation, Space, and Environmental Medicine. 80 (12): 1077. doi:10.3357/ASEM.26010.2009. PMID20027862.
Haber, Fritz; Haber, Heinz (1950). "Possible methods of producing the gravity-free state for medical research". Journal of Aviation Medicine. 21 (5): 395–400. PMID14778792. Summary of the article: Campbell, Mark R. (2009). "Classics in space medicine. Possible methods of producing the gravity-free state for medical research". Aviation, Space, and Environmental Medicine. 80 (12): 1077. doi:10.3357/ASEM.26010.2009. PMID20027862.