@article{MZM_1973_14_2_a8,
     author = {N. G. Perlova},
     title = {On some second-order rigidity conditions for analytic surfaces},
     journal = {Matemati\v{c}eskie zametki},
     pages = {233--242},
     publisher = {mathdoc},
     volume = {14},
     number = {2},
     year = {1973},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1973_14_2_a8/}
}