%0 Journal Article %A V. I. Berdyshev %T Object visibility for an observer with inaccurately given coordinates %J Trudy Instituta matematiki i mehaniki %D 2009 %P 21-28 %V 15 %N 3 %I mathdoc %U http://geodesic.mathdoc.fr/item/TIMM_2009_15_3_a1/ %G ru %F TIMM_2009_15_3_a1