Barber, Alfred W., author
Parker Publishing Company, Inc., 1980
Buku Referensi
edited by A.D. Austen, R.H. Neale
International Labour Office, 1995
Buku Referensi
Carlsen, G. Robert
Harper & Row, 1971
Buku Referensi
Bell, Steven J., author
[American Library association, American Library association], 2007
eBooks
Bell, Suzanne S., author
Libraries Unlimited, 2015
Buku Teks