@article{10_4153_CMB_2017_074_6,
     author = {Rosales, Leobardo},
     title = {Generalizing {Hopf{\textquoteright}s} {Boundary} {Point} {Lemma}},
     journal = {Canadian mathematical bulletin},
     pages = {183--197},
     year = {2019},
     volume = {62},
     number = {1},
     doi = {10.4153/CMB-2017-074-6},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-2017-074-6/}
}