Hochstadt, Harry
John Wiley & Sons, 1973
Buku Teks SO
Wing, G.M., 1923-
Society for Industrial and Applied Mathematics, 1991
eBooks
Polyanin, Andrei D.
Chapman &Hall/CRC, 2008
Buku Referensi
Zemyan, Stephen M.
Springer, 2012
eBooks
Das, Ashok
World Scientific, 1989
Buku Teks SO