00692naa#a2200181#i#450# EN\\bibl\29340 20241229061448.7 2071-7318 20160625b2016####ek#y0engy0150####ca RU APPROBATION OF ECONOMIC AND MATHEMATICAL MODELS IN ACTIVITY OF THE ENTERPRISES WITH THE HELP OF USING MICROSOFT EXCEL AND MATHCAD PROGRAMS Journal article Belgorod Belgorod State Technological University named after V.G. Shukhov 2016 7 с. Journal article local Экономика. Экономические науки. 33 Chikina Elena Dmitrievna Shevchenko M.V. naukaru.ru