Artikel Jurnal
López, Ana Belen Cristobal, editor
Springer, 2012
eBooks
edited by Cecile L. Paris, William R. Swartout, William C. Mann
Kluwer Academic , 1991
Buku Teks
Rich, Elaine, author
Tata McGraw-Hill, 2009
Buku Teks
Sandi Setiawan, author
Andi, 1993
Buku Teks