@article{IM2_1997_61_5_a3,
     author = {Yu. B. Orochko},
     title = {Some properties of the deficiency indices of symmetric singular elliptic second-order operators in~$L^2(\mathbb R^m)$},
     journal = {Izvestiya. Mathematics },
     pages = {969--994},
     publisher = {mathdoc},
     volume = {61},
     number = {5},
     year = {1997},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_1997_61_5_a3/}
}