@article{10_4153_S0008439520000454,
     author = {Harlander, Jens and Rosebrock, Stephan},
     title = {Relative vertex asphericity},
     journal = {Canadian mathematical bulletin},
     pages = {292--305},
     year = {2021},
     volume = {64},
     number = {2},
     doi = {10.4153/S0008439520000454},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/S0008439520000454/}
}