@article{DAN_1970_190_6_a0,
     author = {A. A. Arsen'ev and V. A. Il'in},
     title = {mean value formula for the fundamental functions of the {Beltrami} operator, and a precise estimate of the sum of the squares of the fundamental functions},
     journal = {Doklady Akademii Nauk},
     pages = {1263--1266},
     publisher = {mathdoc},
     volume = {190},
     number = {6},
     year = {1970},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1970_190_6_a0/}
}