APA

Clark W.R, . (1964). Explorers of the World. New York: Express Publishing.

Chicago

Clark W.R, . 1964. Explorers of the World. New York: Express Publishing.

Harvard

Clark W.R, . (1964). Explorers of the World. New York: Express Publishing.

MLA

Clark W.R, . Explorers of the World. New York: Express Publishing. 1964.