TY JOUR TI Differential mathematical models as a method of studying the dynamics of the number of students KW differential mathematical model KW competing groups KW the quality of knowledge. JO Actual directions of scientific researches of the XXI century: theory and practice AU Kumitskiy, B.M. AU Borisova, N.. AU Cavrasova, N.. PY 2015 IS 3 PB FSBE Institution of Higher Education Voronezh State University of Forestry and Technologies named after G.F. Morozov