Παραπομπή σε μορφή APA (7η εκδ.)

Zeylstra, W. G. (1975). Aid or development: The relevance of development aid to problems of developing countries. A.W. Sijthoff.

Παραπομπή σε μορφή Chicago (17η εκδ.)

Zeylstra, Willem Gustaaf. Aid or Development: The Relevance of Development Aid to Problems of Developing Countries. Leyden: A.W. Sijthoff, 1975.

Παραπομπή σε μορφή MLA (9th εκδ.)

Zeylstra, Willem Gustaaf. Aid or Development: The Relevance of Development Aid to Problems of Developing Countries. A.W. Sijthoff, 1975.