@article{10_4171_ggd_144,
     author = {Robert Young},
     title = {Homological and homotopical higher-order filling functions},
     journal = {Groups, geometry, and dynamics},
     pages = {683--690},
     year = {2011},
     volume = {5},
     number = {3},
     doi = {10.4171/ggd/144},
     url = {http://geodesic.mathdoc.fr/articles/10.4171/ggd/144/}
}