APA

CALLAHAN S., . (2011). Called to Happiness: Where faith an psychology meet. New York: Orbis books.

Chicago

CALLAHAN Sidney, . 2011. Called to Happiness: Where faith an psychology meet. New York: Orbis books.

Harvard

CALLAHAN S., . (2011). Called to Happiness: Where faith an psychology meet. New York: Orbis books.

MLA

CALLAHAN Sidney, . Called to Happiness: Where faith an psychology meet. New York: Orbis books. 2011.