Kumar, Krishan
Blackwell, 1996
Buku Teks SO
Greenberg, Miriam
Routledge, 2008
Buku Teks SO
Yelavich, Susan
Phaidon, 2007
Buku Referensi
Harris, Jonathan
Wiley Blackwell, 2017
Buku Teks SO
edited by Ian Harris ... [and others]
Longman Current Affairs, 1992
Buku Teks SO