References
- K. Harada, Moonshine of finite groups, The Ohio State University Lecture Notes.
- T. Miyake, Modular forms, Springer, 1989.
- J. Sturm, On the congruence of modular forms, Number theory (New York, 1984-1985), 275-280, Lecture Notes in Math., 1240, Springer, Berlin, 1987.