Helling, Pam, author
[American Management Association, ], 1992
eBooks
Blumenthal, Joseph C.
Harcourt Brace Jovanovich, 1972
Buku Teks
Camp, Sue C., author
Glencoe/McGraw-Hill, 2001
Buku Teks
Camp, Sue C., author
McGraw-Hill, 2001
Multimedia
Vaccari, Oreste
Charles E. Tuttle, 1952
Buku Teks