@article{DVMG_2020_20_2_a10,
     author = {V. Ya. Prudnikov},
     title = {The problem of separation of variables},
     journal = {Dalʹnevosto\v{c}nyj matemati\v{c}eskij \v{z}urnal},
     pages = {227--233},
     publisher = {mathdoc},
     volume = {20},
     number = {2},
     year = {2020},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DVMG_2020_20_2_a10/}
}