Hegar, Kathryn
Houghton Mifflin, 1985
Buku Teks
Keith, Lyman A., author
McGraw-Hill, 1975
Buku Teks
Paulson, Edward, author
Prenada Media, 2003
Buku Teks
Griffin, Ricky W., author
Pearson Education International, 2006
Buku Teks
Griffin, Ricky W., author
Prentice-Hall, 1999
Buku Teks