@article{10_4064_fm_65_2_129_132,
     author = {J. Gresser},
     title = {The range of a planar function with ambiguous points},
     journal = {Fundamenta Mathematicae},
     pages = {129--132},
     publisher = {mathdoc},
     volume = {65},
     number = {2},
     year = {1969},
     doi = {10.4064/fm-65-2-129-132},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/fm-65-2-129-132/}
}