Yoon, Sung-Hwa; Moon, Ho-Sang; Hwang, Sung-Kwan; Choi, Seungryong; Kang, Suk-Ku Bioorganic and Medicinal Chemistry, 1998, vol. 6, # 7 p. 1043 - 1049 doi: 10.1016/S0968-0896(98)00062-5