Johnson, Robert David (1997). "Anti-Imperialism And The Good Neighbour Policy: Ernest Gruening and Puerto Rican Affairs, 1934–1939". Journal of Latin American Studies. 29 (1): 89–110. doi:10.1017/S0022216X96004634. (Argues Gruening tried to implement the anti-imperialist principles he had outlined in the 1920s. He failed because he lacked local support.)
Naske, Claus-M (2004). Ernest Gruening: Alaska's Greatest Governor. University of Alaska Press. ISBN1-889963-35-6.