APA

Simpson H. N., . (1980). Invisible armies : the impact of disease on american history. New York: Merrell Publishers.

Chicago

Simpson Howard N, . 1980. Invisible armies : the impact of disease on american history. New York: Merrell Publishers.

Harvard

Simpson H. N., . (1980). Invisible armies : the impact of disease on american history. New York: Merrell Publishers.

MLA

Simpson Howard N, . Invisible armies : the impact of disease on american history. New York: Merrell Publishers. 1980.