edited by A.D. Austen, R.H. Neale
International Labour Office, 1995
Buku Referensi
Bonda, Penny, author
Wiley, 2007
Buku Teks
Foster, Kari, author
John Wiley & Sons, 2007
Buku Teks
Piotrowski, Christine M., author
Wiley, 1999
Buku Teks
Cottrell, Michelle, author
John Wiley & Sons, 2011
Buku Teks