@article{10_4064_fm_131_2_83_92,
     author = {A. van Rooij and W. Schikhof},
     title = {On derivatives of functions defined on disconnected sets, {I}},
     journal = {Fundamenta Mathematicae},
     pages = {83--92},
     publisher = {mathdoc},
     volume = {131},
     number = {2},
     year = {1988},
     doi = {10.4064/fm-131-2-83-92},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/fm-131-2-83-92/}
}