Viswanathan, Madhu
SAGE Publ., 2005
Buku Teks
Judd, Charles M.
Methuen, 1991
Buku Teks
Louise H. Kidder
Holt, Rinehart and Winston, 1981
Buku Teks
Lee, Raymond M.
Open University Press, 2000
Buku Teks SO
Babbie, Earl R.
Wadsworth and Cengage Learning, 2013 (International edition)
Buku Teks