Brown; Kinnick; Morin Jr.; Vasileff; Counter; Davidson; Ensminger; Eudaly; Kasher; Katner; Koehler; Kurz; Lindstrom; Lunn; Preston; Ott; Quay; Shadle; Steinberg; et al. Journal of Medicinal Chemistry, 1990, vol. 33, # 8 p. 2114 - 2121 doi: 10.1021/jm00170a011