@article{IM2_2013_77_3_a8,
     author = {J. Wu and R. V. Mikhailov},
     title = {Homotopy groups as centres of finitely presented groups},
     journal = {Izvestiya. Mathematics },
     pages = {581--593},
     publisher = {mathdoc},
     volume = {77},
     number = {3},
     year = {2013},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_2013_77_3_a8/}
}