@article{JGG_2009_13_2_JGG_2009_13_2_a9,
     author = {H. Kaufmann },
     title = {Dynamic {Differential} {Geometry} in {Education}},
     journal = {Journal for geometry and graphics},
     pages = {241--254},
     publisher = {mathdoc},
     volume = {13},
     number = {2},
     year = {2009},
     url = {http://geodesic.mathdoc.fr/item/JGG_2009_13_2_JGG_2009_13_2_a9/}
}