edited by Glyn W. Humphreys
Psychology Press, 1999
Buku Teks SO
Baehr, Mathias
Thieme, 2012
Buku Teks SO
edited by J. Richard Jennings, Michael G.H. Coles
John Wiley & Sons, 1991
Buku Referensi
Macey, Robert I.
Prentice-Hall, 1968
Buku Teks SO
Bainbridge, F.A.
Longman, Green, 1919
Buku Teks SO