Bertol, Daniela, author
John Wiley & Sons, 1997
Buku Teks
Duchacek, Ivo D., author
Santa Barbara, 1973
Buku Teks
Kohnke, Mary F.
Mosby , 1982
Buku Teks
Macarov, David
Sage Publications , 1982
Buku Teks
Martin, J. R., author
Oxford University Press , 1989
Buku Teks