Schlagintweit, Emil (2006) Buddhism in Tibet: Illustrated by Literary Documents and Objects Of Religious Worship With An Account Of The Buddhist Systems Preceding It In IndiaISBN 1-428-64999-9
Stein, R. A. (1962) Tibetan Civilization. First English edition - translated by J. E. Stapleton Driver (1972). Reprint (1972): Stanford University Press, Stanford, California ISBN 0-8047-0806-1 (cloth); ISBN 0-8047-0901-7
Tucci, Giuseppe. The Religions of Tibet. (1970). First English edition, translated by Geoffrey Samuel (1980). Reprint: (1988), University of California Press ISBN 0-520-03856-8 (cloth); ISBN 0-520-064348-1 (pbk)