Willis, H. P. (1976). Our Philippine problem: A study of American colonial policy [microform]. Photoduplication Service, University of the Philippines Library.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Willis, Henry Parker. Our Philippine Problem: A Study of American Colonial Policy [microform]. Quezon City: Photoduplication Service, University of the Philippines Library, 1976.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)Willis, Henry Parker. Our Philippine Problem: A Study of American Colonial Policy [microform]. Photoduplication Service, University of the Philippines Library, 1976.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.