@article{SM_2005_196_10_a4,
     author = {D. V. Osipov},
     title = {Central extensions and reciprocity laws on algebraic surfaces},
     journal = {Sbornik. Mathematics},
     pages = {1503--1527},
     publisher = {mathdoc},
     volume = {196},
     number = {10},
     year = {2005},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_2005_196_10_a4/}
}