TY JOUR TI THE EFFICIENCY ASSESSMENT OF THE TRACTORS K-744P SERIES USE FOR THE SOIL MAIN PROCESSING KW factor costs and costs per unit KW soil processing KW technology KW tractor KW efficiency JO Bulletin of KSAU AU Selivanov, N.I. AU Zaprudskiy, V.N. PY 2013 IS PB Krasnoyarsk State Agrarian University