@article{10_4064_fm_77_2_191_193,
     author = {H. Toru\'nczyk},
     title = {A simple proof of {Hausdorff's} theorem on extending metrics},
     journal = {Fundamenta Mathematicae},
     pages = {191--193},
     publisher = {mathdoc},
     volume = {77},
     number = {2},
     year = {1972},
     doi = {10.4064/fm-77-2-191-193},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/fm-77-2-191-193/}
}