edited by Jeanne Mager Stellman
International Labour Office, 1998
Buku Referensi
Gibbon, Edward, author
Random House, 1994
Buku Referensi
edited by A.D. Boardman
John Wiley & Sons, 1980
Buku Teks
Needham, Joseph, author
University Press, 1954
Buku Referensi
edited by Mona Baker
Routledge, 2009
Buku Teks