Mumford, B. (1969). 15 Steps out. Logos international.
Cita Chicago (17th ed.)Mumford, Bob. 15 Steps Out. Plainfield,NJ: Logos international, 1969.
Cita MLA (9th ed.)Mumford, Bob. 15 Steps Out. Logos international, 1969.
Atenció: Aquestes cites poden no estar 100% correctes.