@article{10_4064_cm113_1_3,
     author = {Andrzej Nowicki},
     title = {An example of a simple derivation in two variables},
     journal = {Colloquium Mathematicum},
     pages = {25--31},
     publisher = {mathdoc},
     volume = {113},
     number = {1},
     year = {2008},
     doi = {10.4064/cm113-1-3},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/cm113-1-3/}
}