Artikel Jurnal
edited by Robert N. Singer, Milledge Murphey and L. Keith Tennat
Macmillan, 1993
Buku Referensi
Yuriantin, author
2015
UI - Tugas Akhir
Mellion, Morris B., author
Hanley & Belfus, 1994
Buku Teks
Pargman, David
Prentice-Hall, 1998
Buku Teks