Goulding, Christina, author
Sage, 2002
Buku Teks
Bell, Judith, author
McGraw-Hill Education, 2014
Buku Teks
Ermentrout, Bard, author
Society for Industrial and Applied Mathematics, 2002
eBooks
Brewerton, Paul
Sage, 2004
Buku Teks
Hajnal, Peter I., author
New York : Oceana Publications, 1978,
Buku Referensi