Ken Yasukawa, So Yeon Yu, Shigetoshi Tsutsumi, Masahiko Kurokawa, and Yong K. Park. “Inhibitory Effects of Brazilian Propolis on Tumor Promotion in Two-Stage Mouse Skin Carcinogenesis”. Journal of Pharmacy and Nutrition Sciences, vol. 2, no. 1, Jan. 2012, pp. 71-76, doi:10.6000/1927-5951.2012.02.01.10.