Olver, F. W. J.
Academic Press, 1974
Buku Teks
Askey, Richard A., author
Society for Industrial and Applied Mathematics, 1975
eBooks
Carlson, B.C., author
Academic Press , 1977
Buku Teks
Roberts, Charles E.
Prentice-Hall, 1979
Buku Teks
Celia, Michael A.
Prentice-Hall, 1992
Buku Teks