Lapiere, R.T.
McGraw-Hill , 1942
Buku Teks
Michener, Andrew, author
Thomson, 2004
Buku Teks
Baron, Robert A., author
Allyn and Bacon , 1997
Buku Teks
Freedman, Jonathan L., author
Prentice-Hall, 1970
Buku Teks
Myers, David G., author
McGraw-Hill, 1996
Buku Teks