@article{JGG_2009_13_2_JGG_2009_13_2_a7,
     author = {N. Bokan and M. Ljucovic and S. Vukmirovic },
     title = {Computer-Aided {Teaching} of {Descriptive} {Geometry}},
     journal = {Journal for geometry and graphics},
     pages = {221--229},
     publisher = {mathdoc},
     volume = {13},
     number = {2},
     year = {2009},
     url = {http://geodesic.mathdoc.fr/item/JGG_2009_13_2_JGG_2009_13_2_a7/}
}