@article{DAN_1963_148_3_a12,
     author = {Ya. A. Roitberg and Z. G. Sheftel},
     title = {Energy inequalities for elliptic operators with discontinuous coefficients and for general boundary conditions and conjugacy conditions},
     journal = {Doklady Akademii Nauk},
     pages = {531--533},
     publisher = {mathdoc},
     volume = {148},
     number = {3},
     year = {1963},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1963_148_3_a12/}
}