@article{EXMA_1998__7_3_226747,
     author = {Alperin, Roger C.},
     title = {Platonic triangles of groups.},
     journal = {Experimental mathematics},
     pages = {191--219},
     publisher = {mathdoc},
     volume = {7},
     number = {3},
     year = {1998},
     zbl = {0959.20039},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EXMA_1998__7_3_226747/}
}