@article{TRSPY_1965_76_a2,
     author = {Yu. F. Borisov},
     title = {A~half-neighborhood and the variation of length of a~curve on a~surface},
     journal = {Informatics and Automation},
     pages = {26--48},
     publisher = {mathdoc},
     volume = {76},
     year = {1965},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TRSPY_1965_76_a2/}
}