Boalt, Gunnar, author
John Wiley & Sons, 1970
Buku Teks
Leonard, Karen Isaksen, author
Sage, 2003
Buku Teks
Harris, Myra A., author
Prentice-Hall, 1997
Buku Teks
Myers, John G., author
Prentice-Hall, 1980
Buku Teks
Bander, Edward J., author
Balinger, 1978
Buku Teks