@article{TRSPY_2009_266_a8,
     author = {S. A. Melikhov},
     title = {The van {Kampen} {Obstruction} and {Its} {Relatives}},
     journal = {Informatics and Automation},
     pages = {149--183},
     publisher = {mathdoc},
     volume = {266},
     year = {2009},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/TRSPY_2009_266_a8/}
}