TY JOUR TI THEORETICAL RESEARCH ROLLER FOR SMALL TILLAGE MACHINE KW walk-behind tractor KW roller KW mechanical system KW the stiffness of the springs KW the kinetic energy KW the Euler equation KW equation Lagrange JO Vestnik of Kazan State Agrarian University AU Yunusov, G.S. AU Anderzhanova, N.N. AU Aleshkin, A.V. AU Ziganshin, B.G. AU Haliullin, D.T. PY 2021 IS 16 PB Kazan state agrarian University