@article{SM_1987_56_2_a13,
     author = {V. V. Lychagin and B. Yu. Sternin},
     title = {On the microlocal structure of pseudodifferential operators},
     journal = {Sbornik. Mathematics},
     pages = {515--527},
     publisher = {mathdoc},
     volume = {56},
     number = {2},
     year = {1987},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1987_56_2_a13/}
}