TY - JOUR AU - A. I. Schetnikov TI - A Sum of Angles of a Self-intersecting Polygon JO - Matematičeskoe obrazovanie PY - 2004 SP - 78 EP - 86 VL - 28 IS - 1 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/MO_2004_28_1_a2/ LA - ru ID - MO_2004_28_1_a2 ER -