@article{TMF_1992_92_3_a8,
     author = {Yu. G. Shondin},
     title = {Perturbation of differential operators on high-codimension manifold and the extension theory for symmetric linear relations in an indefinite metric space},
     journal = {Teoreti\v{c}eska\^a i matemati\v{c}eska\^a fizika},
     pages = {466--472},
     publisher = {mathdoc},
     volume = {92},
     number = {3},
     year = {1992},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/TMF_1992_92_3_a8/}
}