Hartmann, G. W. (1941). Educational psychology. American Book Company.
Cita Chicago (17th ed.)Hartmann, George Wilfried. Educational Psychology. New York, Cincinnati: American Book Company, 1941.
Cita MLA (9th ed.)Hartmann, George Wilfried. Educational Psychology. American Book Company, 1941.
Atenció: Aquestes cites poden no estar 100% correctes.