Holler, Frederick L., author
ABC-Clio, 1981
Buku Teks
Prytherch, Ray, author
Gower, 1987
Buku Referensi
Blazek, Ron, author
Libraries Unlimited, 2000
Buku Referensi
Stewart, David W., author
Sage, 1984
Buku Teks
Antony, Arthur, author
John Wiley & Sons, 1979
Buku Teks