@article{SM_1968_5_4_a5,
     author = {V. Z. Polyakov},
     title = {On extension of {Cartesian} products},
     journal = {Sbornik. Mathematics},
     pages = {559--569},
     publisher = {mathdoc},
     volume = {5},
     number = {4},
     year = {1968},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1968_5_4_a5/}
}