@article{SM_1998_189_7_a1,
     author = {V. V. Golovchanskii},
     title = {Asymptotic behaviour of the~spectral function of {the~Laplace--Beltrami} operator for cocompact discrete subgroups of $\operatorname {SL}_2(\mathbb R)$},
     journal = {Sbornik. Mathematics},
     pages = {977--990},
     publisher = {mathdoc},
     volume = {189},
     number = {7},
     year = {1998},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1998_189_7_a1/}
}