Goldthorpe, J. E., author
Cambridge University PRess, 1975
Buku Teks
Kanshik, Devendra
Sterling Publisher PVT LTD, 1975
Buku Teks
Norbu, Dawa
Routledge, 1995
Buku Teks
Barke, Michael, author
Longman Scientific & Technical, 1991
Buku Teks
Tow, William T., author
Lynne Rienner, 1990
Buku Teks