TY JOUR TI Efficient operation of the tractor in the unit with machine a variable mass KW tractor KW workflow KW the fuel consumption KW variable mas. JO Actual directions of scientific researches of the XXI century: theory and practice AU Shulyak, M.. PY 2015 IS 3 PB FSBE Institution of Higher Education Voronezh State University of Forestry and Technologies named after G.F. Morozov