@article{10_4153_CJM_2010_052_5,
     author = {Bjorndahl, Christina and Karshon, Yael},
     title = {Revisiting {Tietze{\textendash}Nakajima:} {Local} and {Global} {Convexity} for {Maps}},
     journal = {Canadian journal of mathematics},
     pages = {975--993},
     year = {2010},
     volume = {62},
     number = {5},
     doi = {10.4153/CJM-2010-052-5},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-2010-052-5/}
}