National Development Group for Educational Innovation & Sumagaysay, L. S. (1980). In-service education for primary teachers: Design formulation. National Development Group for Educational Innovation.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)National Development Group for Educational Innovation و Lourdes S. Sumagaysay. In-service Education for Primary Teachers: Design Formulation. Manila: National Development Group for Educational Innovation, 1980.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)National Development Group for Educational Innovation و Lourdes S. Sumagaysay. In-service Education for Primary Teachers: Design Formulation. National Development Group for Educational Innovation, 1980.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.