Cita APA (7th ed.)
Howard, P. (1961). Frank Buchman's secret ([1st American ed.].). Doubleday.
Cita Chicago (17th ed.)
Howard, Peter. Frank Buchman's Secret. [1st American ed.]. Garden City, N. Y.: Doubleday, 1961.
Cita MLA (9th ed.)
Howard, Peter. Frank Buchman's Secret. [1st American ed.]. Doubleday, 1961.
Atenció: Aquestes cites poden no estar 100% correctes.