@article{SJIM_2009_12_4_a1,
     author = {R. A. Bogdanova},
     title = {The {Groups} of {Motions} of {Two-Dimensional} {Helmholtz} {Geometries} as {Solutions} to {Functional} {Equations}},
     journal = {Sibirskij \v{z}urnal industrialʹnoj matematiki},
     pages = {12--22},
     publisher = {mathdoc},
     volume = {12},
     number = {4},
     year = {2009},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/SJIM_2009_12_4_a1/}
}