TY JOUR TI Rotation on the boundary of multiply connected region and the singular points of vector fields KW vector field KW rotation of vector fields JO Actual directions of scientific researches of the XXI century: theory and practice AU Shcherbakova, K.. PY 2014 IS 2 PB FSBE Institution of Higher Education Voronezh State University of Forestry and Technologies named after G.F. Morozov