Spencer, Donald D.
Ginn-Blaisdell, 1968
Buku Referensi
Spencer, Donald D.
Camelot Publishing Company, 1993
Buku Referensi
Levin, Richard B., author
Osborne McGraw-Hill, 1990
Buku Referensi
Mortenson, Michael E., author
Industrial Press, 1990
Buku Referensi
edited by Sheldon S.L. Chang
John Wiley & Sons, 1983
Buku Referensi