@article{MZM_1984_35_6_a6,
     author = {Yu. E. Anikonov},
     title = {A criterion for two-dimensional {Riemann} spaces of zero curvature},
     journal = {Matemati\v{c}eskie zametki},
     pages = {841--845},
     publisher = {mathdoc},
     volume = {35},
     number = {6},
     year = {1984},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1984_35_6_a6/}
}