Libes, Sol
Osborne/McGraw-Hil, 1981
Buku Teks
Long, Larry E., author
Prentice-Hall, 1992
Buku Referensi
Osborne, Adam, author
McGraw-Hill, 1983
Buku Teks
Capron, H.L., author
The Benjamin / Cumming Publishing Company Inc., 1989
Buku Teks
McGraw-Hill , 1984
Buku Teks