00548naa#a2200169#i#450# EN\INFRA-M\bibl\13073 20260302050507.1 1998-0728 20160817b2016####ek#y0engy0150####ca RUS RU Development of Ideas of Math Education of Younger Schoolchildren in Soviet School in 30-50-ies of the XX Century Journal article Moscow INFRA-M Academic Publishing LLC. 2016 5 с. Journal article local Kochurova Elena Eduardovna naukaru.ru