Ishwaran, Karigoudar
Westview Press, 1992
Buku Teks SO
Talbot, Ian
Yale University Press, 2016
Buku Teks
Leifer, Michael
Routledge, 1995
Buku Referensi
Leifer, Michael
Routledge, 1996
Buku Referensi
Dian A.H. Shah
Cambridge University Press, 2017
Buku Teks