Philippine Rice Research Institute. (2009). OPAPA: The Open Academy for Philippine Agriculture : an innovation in accessing modern agricultural technologies. Philippine Rice Research Institute.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Philippine Rice Research Institute. OPAPA: The Open Academy for Philippine Agriculture : An Innovation in Accessing Modern Agricultural Technologies. Nueva Ecija: Philippine Rice Research Institute, 2009.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)Philippine Rice Research Institute. OPAPA: The Open Academy for Philippine Agriculture : An Innovation in Accessing Modern Agricultural Technologies. Philippine Rice Research Institute, 2009.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.