APA

Keller J. G., . (1948). You can change the world: the Christopher approach. New York: Longmans.

Chicago

Keller James Gregory, . 1948. You can change the world: the Christopher approach. New York: Longmans.

Harvard

Keller J. G., . (1948). You can change the world: the Christopher approach. New York: Longmans.

MLA

Keller James Gregory, . You can change the world: the Christopher approach. New York: Longmans. 1948.