Cronin, Jane
"New York: Marcel Dekker, 1994",
Buku Teks
Mattheij, Robert M.M.
Society for Industrial and Applied Mathematics, 2002
eBooks
Sergey Leble, author
TASK, 2017
Artikel Jurnal
Lefschetz, Solomon
Dover , 1977
Buku Teks
Demengel, Françoise, author
[Springer, ], 2012
eBooks