Marshall, W.T.
Pitman, 1978
Buku Teks
Bhatt, P., author
Longman Scientific and Technical, 1990
Buku Teks
edited by M. Ivanyi and M. Skaloud
Springer-Verlag, 1992
Buku Teks
Birkhoff, Garrett, author
Society for Industrial and Applied Mathematics, 1984
eBooks
Dunham, Clarence W.
McGraw-Hill, 1962
Buku Teks