@article{10_4064_fm_105_2_79_85,
     author = {Richard Tondra},
     title = {Homeotopy groups of surfaces whose boundary is the union of 1-spheres},
     journal = {Fundamenta Mathematicae},
     pages = {79--85},
     publisher = {mathdoc},
     volume = {105},
     number = {2},
     year = {1979},
     doi = {10.4064/fm-105-2-79-85},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/fm-105-2-79-85/}
}