For citations:
Shabalin A.N. . Statistics and Economics. 2013;(2):179-181. (In Russ.) https://doi.org/10.21686/2500-3925-2013-2-179-181
Shabalin A.N. . Statistics and Economics. 2013;(2):179-181. (In Russ.) https://doi.org/10.21686/2500-3925-2013-2-179-181