Coppock, Joseph D.
McGraw-Hill, 1959
Buku Teks
by Curtis E. Tate Jr. ... [and others]
Business Publication, 1982
Buku Teks
Olson, Charles L., author
Scott, Foresman, 1983
Buku Teks
Hornby, Win, author
Prentice-Hall, 2001
Buku Teks
Hague, D.C., author
Longman, 1971
Buku Teks