Crow, Lester D., author
American Book Comp, 1956
Buku Teks
Nagel, Michael C., author
Oxford University Press, 2016
Buku Teks
Omrod, Jeanne Ellis, author
Pearson Education, Inc., 2009
Buku Teks
National Training Laboratories Institute for Applied Behavioral Science
Institute for Applied Behavioral Science, 1968
Buku Teks
Ormrod, Jeanne Ellis, author
Macmillan, 1990
Buku Teks