Edwards, James Don, author
R. D. Irwin, 1967
Buku Teks
Schure, Alexander, author
McGraw-Hill, 1978
Buku Teks
Edwards, James Don, author
Richard D. Irwin, 1968
Buku Teks
Horton, Paul B., author
Dow Jones Irwin, 1982
Buku Teks
Ryan, William
Learning System of Company, 1971
Buku Teks