Perkin, G. W. (1968). Population and family planning in the Philippines. Ford Foundation.
Lua i Stíl Chicago (17ú heag.)Perkin, Gordon W. Population and Family Planning in the Philippines. Bangkok: Ford Foundation, 1968.
Lua MLA (9ú heag.)Perkin, Gordon W. Population and Family Planning in the Philippines. Ford Foundation, 1968.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.