Degradation Index for Quality Evaluation of Commercial Dietary Supplements of Bilberry Extract (2013) 【2013】Masao Yamamoto, Katsunori Yamaura, Makiko Ishiwatari, Maki Shimada, Sayaka Kado, Hiroko Seki, Norimoto Shimada, and Koichi Ueno.Chiba University, TOKIWA Phytochemical Co., Ltd.Journal of Food Science, 78(3) 477-483. (2013)