Freeman, Roger L., author
Wiley, 1985
Buku Referensi
Freeman, Roger L.
John Wiley & Sons, 1991
Buku Referensi
Lindeburg, Michael R., author
Professional Publications, 1984
Buku Teks
Stephens, Wendell B., author
McGraw-Hill, 1985
Buku Referensi
Dunlop, J.
Chapman & Hall, c1994
Buku Teks