French, Sally, author
Butterworth-Heinemann, 2001
Buku Referensi
edited by A.D. Austen, R.H. Neale
International Labour Office, 1995
Buku Referensi
Langer, Arthur M., editor
Springer, 2012
eBooks
Oades, Lindsay G., author
Sage, 2019
Buku Teks
edited by Janet Holmes and Kirk Hazen
John Wiley & Sons, 2014
Buku Teks