[1] K. Conrad, Characters of nite ab elian groups, http://www.math.uconn.edu/~kconrad/blurbs/grouptheory/charthy.pdf.
[2] K. Conrad, The origin of representation theory, http://www.math.uconn.edu/~kconrad/articles/groupdet.pdf.
[3] I. M. Isaacs, Character Theory of Finite Groups, Academic Press, New York, London, 1976.
[4] B. L. van der Waerden, A History of Algebra, From al-Khwarizmi to Emmy No ether, Springer-Verlag, Berlin, 1985.