@article{MZM_1988_44_5_a7,
     author = {N. V. Ivanov},
     title = {Rank of {Teichm\"uller} modular groups},
     journal = {Matemati\v{c}eskie zametki},
     pages = {636--644},
     publisher = {mathdoc},
     volume = {44},
     number = {5},
     year = {1988},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1988_44_5_a7/}
}