@article{IM2_1984_23_2_a6,
     author = {N. G. Kruzhilin},
     title = {An estimate of the variation of a~normal parameter of a~chain on a~pseudoconvex surface},
     journal = {Izvestiya. Mathematics },
     pages = {367--389},
     publisher = {mathdoc},
     volume = {23},
     number = {2},
     year = {1984},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_1984_23_2_a6/}
}