APA (7e ed.) Bronvermelding

Elshafei, A. (1968). Product Performance Models PPM. The Institute of National Planning.

Chicago (17e ed.) Bronvermelding

Elshafei, Alwalid. Product Performance Models PPM. Cairo: The Institute of National Planning, 1968.

MLA (9e ed.) Bronvermelding

Elshafei, Alwalid. Product Performance Models PPM. The Institute of National Planning, 1968.

Let op: Deze citaties zijn niet altijd 100% accuraat.