JONES, BESSIE Z.; BOYD, LYLE G. The Harvard College Observatory: The First Four Directorships, 1839-1919. [s.l.]: Belknap Press of Harvard University Press, 1971. Dostupné online. ISBN9780674374607. (anglicky)
O'CONNOR, J. J.; ROBERTSON, E. F. (2023). Josef Winlock. mathshistory.st-andrews.ac.uk [online]. School of Mathematics and Statistics, University of St Andrews, Scotland [cit. 2025-05-10]. Dostupné online.