Gaya APA

Payne, J, S., R, I, P, J. (1981). Mental retardation . London: London: A Bell & Howell; 1981.

Gaya MLA

Payne, James, S., R, I., Patton,, James. "Mental retardation". London: London: A Bell & Howell; 1981, 1981. Text.