@article{10_1090_S0894_0347_99_00308_2,
     author = {Bridson, Martin},
     title = {Fractional isoperimetric inequalities and subgroup distortion},
     journal = {Journal of the American Mathematical Society},
     pages = {1103--1118},
     year = {1999},
     volume = {12},
     number = {4},
     doi = {10.1090/S0894-0347-99-00308-2},
     url = {http://geodesic.mathdoc.fr/articles/10.1090/S0894-0347-99-00308-2/}
}