@article{10_4064_fm_44_1_103_114,
     author = {J. Ravetz},
     title = {Derivate planes of continuous functions of two real variables},
     journal = {Fundamenta Mathematicae},
     pages = {103--114},
     publisher = {mathdoc},
     volume = {44},
     number = {1},
     year = {1957},
     doi = {10.4064/fm-44-1-103-114},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/fm-44-1-103-114/}
}