@article{JRAM_1993__436_153502,
     author = {Masakazu Yamagishi},
     title = {On the center of {Galois} groups of maximal pro-p extensions of algebraic number fields with restricted ramification.},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {197--208},
     publisher = {mathdoc},
     volume = {436},
     year = {1993},
     zbl = {0766.11044},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1993__436_153502/}
}