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
Robinson, James R.
Blackwell Scientific, 1975
Buku Teks
Bainbridge, F.A.
Longmans, Green , 1919
Buku Teks