APA

Sugrue F., . (1961). Popes in the modern world. New York: Crowell.

Chicago

Sugrue Francis, . 1961. Popes in the modern world. New York: Crowell.

Harvard

Sugrue F., . (1961). Popes in the modern world. New York: Crowell.

MLA

Sugrue Francis, . Popes in the modern world. New York: Crowell. 1961.