@article{GT_2013_17_3_a12,
     author = {Cooper, Daryl and Futer, David and Purcell, Jessica S},
     title = {Dehn filling and the geometry of unknotting tunnels},
     journal = {Geometry & topology},
     pages = {1815--1876},
     publisher = {mathdoc},
     volume = {17},
     number = {3},
     year = {2013},
     doi = {10.2140/gt.2013.17.1815},
     url = {http://geodesic.mathdoc.fr/articles/10.2140/gt.2013.17.1815/}
}