Astilla, E. C. (1989). Badian-Alegria research project: Upland study. Population/Development Planning and Research Project, National Economic and Development Authority.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Astilla, Estela C. Badian-Alegria Research Project: Upland Study. Pasig, Metro Manila: Population/Development Planning and Research Project, National Economic and Development Authority, 1989.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)Astilla, Estela C. Badian-Alegria Research Project: Upland Study. Population/Development Planning and Research Project, National Economic and Development Authority, 1989.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.