Akaruese, Lucky, author
Xlibris Corporation, 2012
Buku Teks
Friedman, Mark, author
Capstone Global Library, 2012
Buku Teks
penyunting, Peter Davies; penerjemah, A. Rahman Zainuddin
Yayasan Obor Indonesia , 1994
Buku Teks
International Labour Office, 1998
Buku Teks
edited by James C. Hsiung
Paragon House, 1985
Buku Teks