TY JOUR TI Mathematical modelling of indicators of quality of wood KW mathematical model KW wood KW quality KW annual ring KW porosity KW density KW strength JO Actual directions of scientific researches of the XXI century: theory and practice AU Varivodin, V.. PY 2014 IS 2 PB FSBE Institution of Higher Education Voronezh State University of Forestry and Technologies named after G.F. Morozov