00477naa#a2200169#i#450# EN\INFRA-M\bibl\6070 20241221105041.6 2587-9111 20150617b2015####ek#y0engy0150####ca RUS RU Kondratiev Waves in the Economy of Belgium Journal article Moscow INFRA-M Academic Publishing LLC. 2015 4 с. Journal article local Averina Tatyana Nikolaevna naukaru.ru