Seidman, Lisa A.
Prentice-Hall, 2000
Buku Teks SO
Thomas G.M. Schalkhammer, editor
Birkhauser, 2002
Buku Teks SO
Sobti, R.C.
CRC Press, Taylor & Francis Group, 2009
Buku Teks SO
edited by Martin Fransman, Gerd Junne and Annemieke Roobeek
Blackwell, 1995
Buku Teks SO
Lowrie, Pauline
Cambridge University Press, 1994
Buku Teks SO