@article{SM_1999_190_8_a4,
     author = {A. Yu. Savin and B. Yu. Sternin},
     title = {Elliptic operators in even subspaces},
     journal = {Sbornik. Mathematics},
     pages = {1195--1228},
     year = {1999},
     volume = {190},
     number = {8},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1999_190_8_a4/}
}