Seager, Spencer L., author
Scott, Forestman and Company, 1973
Buku Teks
Brown, Theodore L., author
Prentice-Hall, 1991
Buku Teks
Helmprecht, H.L., author
McGraw-Hill, 1977
Buku Teks
Brown, Theodore L., author
Prentice-Hall, 1997
Buku Teks
Brown, Theodore L., author
Prentice-Hall, 1977
Buku Teks