Narayan, Uma
Routledge, 1997
Buku Teks SO
Cammack, Paul Anthony
Macmillan, 1993
Buku Teks SO
edited by T.E. Smith
George Allen and Unwin, 1973
Buku Teks SO
edited by Hamish Main and Stephen Wyn Williams
J. Wiley, 1994
Buku Teks
Norbu, Dawa
Routledge, 1995
Buku Teks SO