Philippine Council for Agriculture, Forestry and Natural Resources Research and Development. Research Information Storage and Retrieval System Committee. (1989). RETRES technical abstracting manual. Philippine Council for Agriculture, Forestry and Natural Resources Research and Development.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Philippine Council for Agriculture, Forestry and Natural Resources Research and Development. Research Information Storage and Retrieval System Committee. RETRES Technical Abstracting Manual. Los Banos, Laguna: Philippine Council for Agriculture, Forestry and Natural Resources Research and Development, 1989.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)Philippine Council for Agriculture, Forestry and Natural Resources Research and Development. Research Information Storage and Retrieval System Committee. RETRES Technical Abstracting Manual. Philippine Council for Agriculture, Forestry and Natural Resources Research and Development, 1989.