1. The Buddha's Doctrine and the Nine Vehicles
2. Cheney, Jim. 1999. “The Journey Home.” In An Invitation to Environmental Philosophy, edited by Anthony Weston, 141–167. Oxford: Oxford University Press.
3. Dalai, Lama. 2005. A Universe in a Single Atom: The Convergence of Science and Spirituality. New York: Morgan Road Books.
4. Evans, Donald. 1992. Spirituality and Human Nature. Albany: SUNY Press.
5. Geshe, Lhundup Sopa, and Jeffrey Hopkins. 1989. Cutting Through Appearances. Ithaca: Snow Lion Publications.