Heffner, R. D. (1956). A documentary history of the United States. The New American Library of World Literature.
Citazione stile Chigago Style (17a edizione)Heffner, Richard D. A Documentary History of the United States. Nueva York: The New American Library of World Literature, 1956.
Citatione MLA (9a ed.)Heffner, Richard D. A Documentary History of the United States. The New American Library of World Literature, 1956.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.