Esoteric teachings of the Tibetan Tantra : including seven initiation rituals and the six yogas of Naropa in Tsong-Kha-Pa's commentary - Tson'-kha-pa Blo-bzan-'grags-pa, 1357-1419; Muses, C. A.; Chang, Chʻêng-chi (York Beach : Weiser, 1982)