Merck and Co., Inc.
Patent: US4156734 A1, 1979 ;

Zhang, Yihua; Yang, Xinye; Xing, Hui; Zhang, Ye; Lai, Yisheng; Jiang, Yongwen; Ma, Dawei
Chinese Journal of Chemistry, 2012 , vol. 30, # 4 p. 875 - 880

Merck and Co., Inc.
Patent: US4156734 A1, 1979 ;