@article{10_4171_ggd_223,
     author = {Kei Nakamura},
     title = {The girth alternative for mapping class groups},
     journal = {Groups, geometry, and dynamics},
     pages = {225--244},
     year = {2014},
     volume = {8},
     number = {1},
     doi = {10.4171/ggd/223},
     url = {http://geodesic.mathdoc.fr/articles/10.4171/ggd/223/}
}