Mitchell, Rosamond, author
Arnold, 1998
Buku Teks
Leaver, Betty Lou, author
Cambridge Press , 2005
Buku Teks
Danuta Gabrys-Barker
Springer, 2012
eBooks
Littlewood, William T.
Cambridge University Press , 1994
Buku Teks
Cambridge University Press, 1989
Buku Teks