@article{ZNSL_1989_170_a2,
     author = {M. S. Birman and M. Z. Solomjak},
     title = {Operator integration, perturbations and commutators},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {34--66},
     publisher = {mathdoc},
     volume = {170},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1989_170_a2/}
}