TY JOUR TI Optimization of technologies of timber rafting on the small rivers KW hydrodynamic resistance KW rafts alloy KW small rivers KW optimization JO Actual directions of scientific researches of the XXI century: theory and practice AU Perfilev, P.. AU Shtaborov, D.. PY 2014 IS 2 PB FSBE Institution of Higher Education Voronezh State University of Forestry and Technologies named after G.F. Morozov