TY  - JOUR
AU  - V. V. Golovchanskii
AU  - M. N. Smotrov
TI  - An explicit formula for the number of classes of primitive hyperbolic elements in the group $\Gamma_0(N)$
JO  - Sbornik. Mathematics
PY  - 2008
SP  - 1009
EP  - 1031
VL  - 199
IS  - 7
UR  - http://geodesic.mathdoc.fr/item/SM_2008_199_7_a3/
LA  - en
ID  - SM_2008_199_7_a3
ER  -