Cangül, İ. N. And Bizim, O. 1998. Normal subgroups of Hecke groups on sphere and torus. Tr. J. of Mathematics , vol.22 , 369-377.

Cangül, İ. N., & Bizim, O., (1998). Normal subgroups of Hecke groups on sphere and torus. Tr. J. of Mathematics , vol.22, 369-377.

Cangül, İSMAİL, And OSMAN BİZİM. "Normal subgroups of Hecke groups on sphere and torus," Tr. J. of Mathematics , vol.22, 369-377, 1998

Cangül, İSMAİL N. And Bizim, OSMAN. "Normal subgroups of Hecke groups on sphere and torus." Tr. J. of Mathematics , vol.22, pp.369-377, 1998

Cangül, İ. N. And Bizim, O. (1998) . "Normal subgroups of Hecke groups on sphere and torus." Tr. J. of Mathematics , vol.22, pp.369-377.

@article{article, author={İSMAİL NACİ CANGÜL And author={OSMAN BİZİM}, title={Normal subgroups of Hecke groups on sphere and torus}, journal={Tr. J. of Mathematics}, year=1998, pages={369-377} }