Young, Pauline V., 1896-, author
Prentice-Hall, 1966
Buku Teks
Crano, William D., author
Lawrence Erlbaum Assossiate, 2002
Buku Teks
edited by Louis Moss and Harvey Goldstein
University of London Institute of Education, 1979
Buku Teks
Alston, Margaret, author
Allen & Unwin, 1998
Buku Teks
Wunsch, Guillaume J., author
Plenum Press, 1978
Buku Teks