Bibliography

• [Kul91]
  Article

  An arithmetic-geometric method in the study of the subgroups of the modular group

  R. S. Kulkarni

  Amer. J. Math.Vol. 113(6)pp. 1053–11331991
• [Ver00]
  Preprint

  Fundamental domain drawing program

  H. A. Verrill

  2000

  http://hverrill.net/fundomain/