Archived from the original on March 9, 2013. In April–May 1970, many North Vietnamese forces entered Cambodia in response to the call for help addressed to Vietnam not by Pol Pot, but by his deputy Nuon Chea. Nguyen Co Thach recalls: 'Nuon Chea has asked for help and we have liberated five provinces of Cambodia in ten days.'^ AP/St. Peterburg Independent.

^ Gitlin, Todd (1987). The Sixties: Years of Hope, Days of Rage. Bantam Books. p. 410. ISBN 978-0-553-37212-0.

^ Safire, pp. 205–209

^ UPI/Beaver County Times & 1970-05-09.

^ Black, pp. 675–676.

^ Ambrose 1989, pp. 446–448.

^ Evans.

^ Ambrose 1991, pp. 53–55.

^ Ambrose 1991, p. 473.

^ Ambrose 1989, pp. 379–383.

^ Jump up to: a b c Kornbluh, Peter (2003). The Pinochet File: A Declassified Dossier on Atrocity and Accountability. New York: The New Press. ISBN 978-1-56584-936-5.

^ Black, p. 921.

^ Jump up to: a b c BBC & 1972-05-22.

^ David Tal, " 'Absolutes' and 'Stages' in the Making and Application of Nixon's SALT Policy."Diplomatic History 37.5 (2013): 1090–1116, quoting pp 1091, 1092. 