@article{CMH_1983__58_139949,
     author = {Ralph Strebel},
     title = {Explicit resolutions for the binary polyhedral groups and for other central extensions of the triangle gorups.},
     journal = {Commentarii mathematici Helvetici},
     pages = {433--452},
     publisher = {mathdoc},
     volume = {58},
     year = {1983},
     zbl = {0541.20035},
     url = {http://geodesic.mathdoc.fr/item/CMH_1983__58_139949/}
}