%0 Journal Article %A S. A. Melikhov %T The van Kampen Obstruction and Its Relatives %J Informatics and Automation %D 2009 %P 149-183 %V 266 %I mathdoc %U http://geodesic.mathdoc.fr/item/TRSPY_2009_266_a8/ %G en %F TRSPY_2009_266_a8