Modular groups

Theta Constants, Riemann Surfaces and the Modular Group

Hershel M. Farkas, Irwin Kra

Elliptic modular functions: an introduction

[by] B. Schoeneberg. Translated from the German by J. R. Smart and E. A. Schwandt.

The Siegel modular variety of degree two and level four

Ronnie Lee, Steven H. Weintraub. Cohomology of the Siegel modular group of degree two and level four / J. William Hoffman, Steven H. Weintraub.

Around theta functions and Siegel modular forms.

Kyōto Daigaku. Sūri Kaiseki Kenkyūjo

Non-Archimedean L-Functions and Arithmetical Siegel Modular Forms (Lecture Notes in Mathematics)

Alexei A. Panchishkin, Michel Courtieu

Siegel's modular forms and dirichlet series

Hans Maass.

Siegel's modular formsand Dirichlet series: course given at the University of Maryland, 1969-1970

Hans Maass.

Lectures on Hilbert modular surfaces

Friedrich Hirzebruch and Gerard van der Geer ; notes by W. Hausmann and F.J. Koll.

Hilbert modular surfaces

[by] Friedrich E. P. Hirzebruch.

Hopf algebras and congruence subgroups

Yorck Sommerhäuser, Yongchang Zhu