Siegel, Laurence
Richard D. Irwin, 1968
Buku Teks SO
Tiffin, Joseph
Prentice-Hall, 1958
Buku Teks
Ghiselli, Edwin E.
McGraw-Hill, 1955
Buku Teks
edited by Charles S. Myers
Oxford University Press, 1956
Buku Teks SO
Aamodt, Michael G.
Wadsworth and Cengage Learning, 2013
Buku Teks SO