@article{IM_1986__86_143401,
     author = {Y. Ihara},
     title = {On {Galois} representations arising from towers of coverings of {P1} ... .},
     journal = {Inventiones mathematicae},
     pages = {427--460},
     year = {1986},
     volume = {86},
     zbl = {0585.14020},
     url = {http://geodesic.mathdoc.fr/item/IM_1986__86_143401/}
}