International Labur Organization, c1977
Buku Teks
Czinkota, Michael R., author
The Dryden Press, 1992
Buku Teks
Loffel, Egon W.
John Wiley & Sons, 1977
Buku Teks
Pride, William M., author
Hougton-Mifflin, 1988
Buku Teks
Garrison, Sharon Hatten
Quorum Books, 1988
Buku Teks