Cohen, A. M. (1971). A constant variable. Jossey-Bass.
Cita Chicago (17th ed.)Cohen, Arthur M. A Constant Variable. San Francisco: Jossey-Bass, 1971.
Cita MLA (9th ed.)Cohen, Arthur M. A Constant Variable. Jossey-Bass, 1971.
Atenció: Aquestes cites poden no estar 100% correctes.