Παραπομπή σε μορφή APA (7η εκδ.)

Villegas, A. E. (1987). A survey on the knowledge, attitude, and practice of family planning among population program professionals in Region XII. Socio-Economic Research Center, Notre Dame University.

Παραπομπή σε μορφή Chicago (17η εκδ.)

Villegas, Alfonso E. A Survey on the Knowledge, Attitude, and Practice of Family Planning Among Population Program Professionals in Region XII. Cotabato City: Socio-Economic Research Center, Notre Dame University, 1987.

Παραπομπή σε μορφή MLA (8th εκδ.)

Villegas, Alfonso E. A Survey on the Knowledge, Attitude, and Practice of Family Planning Among Population Program Professionals in Region XII. Socio-Economic Research Center, Notre Dame University, 1987.