ST. JOHN, P. Wesley K. Wark, The Ultimate Enemy: British Intelligence and Nazi Germany, 1933-1939. Journal of Conflict Studies, [S. l.], v. 7, n. 4, 1987. Disponível em: https://journals.lib.unb.ca/index.php/JCS/article/view/14779. Acesso em: 2 dec. 2021.