TY JOUR TI Improving the Models of Kondratyev Cycles in Economic Dynamics KW Kondratyev cycles KW Fourier series KW models KW periods KW formation moments KW technological modes KW productivity KW forecasts KW crisis JO Scientific Research and Development. Economics AU Basovskiy, L.E. AU Basovskaya, E.N. PY 2022 IS 10 PB INFRA-M Academic Publishing LLC.