@article{SM_1987_56_2_a11,
     author = {D. Schenk and M. A. Shubin},
     title = {Asymptotic expansion of the state density and the spectral function of {a~Hill} operator},
     journal = {Sbornik. Mathematics},
     pages = {473--490},
     publisher = {mathdoc},
     volume = {56},
     number = {2},
     year = {1987},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1987_56_2_a11/}
}