International Labour Office, 1969
Buku Teks
edited by Jeanne Mager Stellman
International Labour Office, 1998
Buku Referensi
Koren, Herman, author
Lewis Publishers, 1996
Buku Referensi
Stellman, Jeanne Mager
International Labour Office, 1998
Buku Referensi
Goetsch, David L., author
Pearson-Prentice Hall, 2005
Buku Teks