@article{IM_1991__106_1_143954,
     author = {F.G. Timmesfeld},
     title = {Groups generated by k-root subgroups.},
     journal = {Inventiones mathematicae},
     pages = {575--666},
     publisher = {mathdoc},
     volume = {106},
     number = {1},
     year = {1991},
     zbl = {0794.20057},
     url = {http://geodesic.mathdoc.fr/item/IM_1991__106_1_143954/}
}