00465naa#a2200169#i#450# EN\INFRA-M\bibl\267 20241223092659.1 2308-4898 20130603b2013####ek#y0engy0150####ca RUS RU How to define a number of roots of equations Journal article Moscow INFRA-M Academic Publishing LLC. 2013 1 с. Journal article local Savelev Yuriy zh-szf.ru