TY - JOUR AU - V. I. Berdyshev TI - Object visibility for a~group of observers with inaccurately given coordinates JO - Trudy Instituta matematiki i mehaniki PY - 2009 SP - 44 EP - 51 VL - 15 IS - 4 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/TIMM_2009_15_4_a4/ LA - ru ID - TIMM_2009_15_4_a4 ER -