Duffy, Daniel J., author
John Wiley & Sons, 2004
Buku Teks
Baxter, Martin
Cambridge university press, 1996
Buku Teks
Gisela, author
Universitas Indonesia, 2016
UI - Skripsi Membership
Lewis, Nigel C.
Thomas Telfors, 1994
Buku Teks
Langsam, Yedidyah, author
Prentice-Hall, 1996
Buku Teks