Ashcraft, Mark H.
Harper Collins, 1994
Buku Teks SO
Stein, Donald G.
Macmillan, 1974
Buku Teks
Ashcraft, Mark H.
Pearson, 2014
Buku Teks SO
edited by Daniel Reisberg and Paula Hertel
Blackwell, 2006
Buku Teks SO
Parkin, Alan C.
John Wiley & Sons, 1999
Buku Teks SO