@article{MZ_1961__76_169965,
     author = {Gert Sabidussi},
     title = {Graph {Derivatives.}},
     journal = {Mathematische Zeitschrift},
     pages = {385--401},
     publisher = {mathdoc},
     volume = {76},
     year = {1961},
     zbl = {0109.16404},
     url = {http://geodesic.mathdoc.fr/item/MZ_1961__76_169965/}
}