@article{ZVMMF_1985_25_2_a7,
     author = {V. I. Gryn'},
     title = {Different $P_N$-approximations of the method of spherical harmonics},
     journal = {\v{Z}urnal vy\v{c}islitelʹnoj matematiki i matemati\v{c}eskoj fiziki},
     pages = {254--268},
     publisher = {mathdoc},
     volume = {25},
     number = {2},
     year = {1985},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZVMMF_1985_25_2_a7/}
}