Rosenberg, Daniel (April 22, 2019). "From Crisis to Split: The Communist Party USA, 1989–1991". American Communist History. 18 (1–2): 1–55. doi:10.1080/14743892.2019.1599627. S2CID159619768.
Kostiainen, Auvo (September 2001). "Hall, Gus (1910–2000)" (in Finnish). The National Biography of Finland. Archived from the original on March 11, 2008. Retrieved April 27, 2010.
Rosenberg, Daniel (April 22, 2019). "From Crisis to Split: The Communist Party USA, 1989–1991". American Communist History. 18 (1–2): 1–55. doi:10.1080/14743892.2019.1599627. S2CID159619768.
Kostiainen, Auvo (September 2001). "Hall, Gus (1910–2000)" (in Finnish). The National Biography of Finland. Archived from the original on March 11, 2008. Retrieved April 27, 2010.