@article{CMH_1954__28_139087,
     author = {George W. Whitehead},
     title = {On mappings into group-like spaces.},
     journal = {Commentarii mathematici Helvetici},
     pages = {320--328},
     publisher = {mathdoc},
     volume = {28},
     year = {1954},
     zbl = {0058.16801},
     url = {http://geodesic.mathdoc.fr/item/CMH_1954__28_139087/}
}