APA

Porter D. R., . (1918). The enrichment of prayer. New York: Association press.

Chicago

Porter David Richard, . 1918. The enrichment of prayer. New York: Association press.

Harvard

Porter D. R., . (1918). The enrichment of prayer. New York: Association press.

MLA

Porter David Richard, . The enrichment of prayer. New York: Association press. 1918.