edited by. Herbert F. Lund
McGraw-Hill, 1971
Buku Referensi
Freeman, Harry M., author
McGraw-Hill, 1971
Buku Referensi
Cooper, C. David, author
Waveland Press, 1986
Buku Teks
Heihnson, Robert Jennings, author
Prentice-Hall, 1999
Buku Teks
Crawford, Martin
Tata McGraw-Hill, 1976
Buku Teks