Cita APA (7th ed.)
Westling David L. (1986). Introduction to mental retardation. Prentice-Hall.
Cita Chicago (17th ed.)
Westling David L. Introduction to Mental Retardation. New Jersey: Prentice-Hall, 1986.
Cita MLA (9th ed.)
Westling David L. Introduction to Mental Retardation. Prentice-Hall, 1986.
Atenció: Aquestes cites poden no estar 100% correctes.