@article{10_37236_3319,
     author = {Bruno Benedetti and Frank H. Lutz},
     title = {Knots in collapsible and non-collapsible balls},
     journal = {The electronic journal of combinatorics},
     year = {2013},
     volume = {20},
     number = {3},
     doi = {10.37236/3319},
     zbl = {1295.57004},
     url = {http://geodesic.mathdoc.fr/articles/10.37236/3319/}
}