Özcan, Musa. “Use of Propolis Extract As a Natural Antioxidant for Plant Oils”. Grasas y Aceites 51, no. 4 (August 30, 2000): 251–253. Accessed June 9, 2023. https://grasasyaceites.revistas.csic.es/index.php/grasasyaceites/article/view/420.