Powell, L. S. (1969). Communication and learning. Pitman.
Cita Chicago (17th ed.)Powell, Leonard Sutherland. Communication and Learning. London: Pitman, 1969.
Cita MLA (8th ed.)Powell, Leonard Sutherland. Communication and Learning. Pitman, 1969.
Atenció: Aquestes cites poden no estar 100% correctes.