edited by L. Andries van der Ark, Marcel A. Croon and Klaas Sijtsma
Lawrence Erlbaum Associates, 2005
Buku Teks
Pirie, Madsen, 1940-
Wildwood House, 1988
Buku Teks
Information Agency, 1973
Buku Teks
Palys, T.S. (Theodore Stephen)
Nelson Education, 2014
Buku Teks SO
edited by Louis Moss and Harvey Goldstein
University of London Institute of Education, 1979
Buku Teks SO