Keep, P. A. v. (1971). Family planning in Mexico D.F.: A study into the knowledge, attitudes and practice of women in Mexico City, comparing data from patients from a family planning clinic with those of other Mexican women (con un resumen en castellano) (met een Samenvatting m het Nederlands).
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Keep, Pieter A. van. Family Planning in Mexico D.F.: A Study into the Knowledge, Attitudes and Practice of Women in Mexico City, Comparing Data from Patients from a Family Planning Clinic with Those of Other Mexican Women (con Un Resumen En Castellano) (met Een Samenvatting M Het Nederlands). Utrecht, 1971.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Keep, Pieter A. van. Family Planning in Mexico D.F.: A Study into the Knowledge, Attitudes and Practice of Women in Mexico City, Comparing Data from Patients from a Family Planning Clinic with Those of Other Mexican Women (con Un Resumen En Castellano) (met Een Samenvatting M Het Nederlands). 1971.