Wilson, Stan Le Roy
McGraw-Hill, 1995
Buku Teks SO
edited by James Curran and Michael Gurevitch
Edward Arnold, 1991
Buku Teks SO
Hollister, Bernard C.
National Textbook, 1991
Buku Teks SO
Routledge , 1997
Buku Teks SO
Mascull, Bill
Harper Collins Publishing, 1995
Buku Teks SO