McGowan, Maryrose
John Wiley & Sons, 1996
Buku Teks
Delmon, Jeffrey
Sweet & Maxwell, 2000
Buku Teks
edited by A.D. Austen, R.H. Neale
International Labour Office, 1995
Buku Referensi
Bonda, Penny
Wiley, 2007
Buku Teks
Foster, Kari
John Wiley & Sons, 2007
Buku Teks