@article{UZKU_1966_126_1_a5,
     author = {L. G. Khrustaleva},
     title = {The $Q$ pair and harmonic normalization of a~congruence},
     journal = {U\v{c}\"enye zapiski Kazanskogo universiteta. Seri\^a Fiziko-matemati\v{c}eskie nauki},
     pages = {50--59},
     publisher = {mathdoc},
     volume = {126},
     number = {1},
     year = {1966},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/UZKU_1966_126_1_a5/}
}