@article{JGG_2009_13_1_JGG_2009_13_1_a6,
     author = {A. Zarei and M. Ghodsi },
     title = {A {Practical} {Approach} for {Planar} {Visibility} {Maintenance}},
     journal = {Journal for geometry and graphics},
     pages = {75--9},
     publisher = {mathdoc},
     volume = {13},
     number = {1},
     year = {2009},
     url = {http://geodesic.mathdoc.fr/item/JGG_2009_13_1_JGG_2009_13_1_a6/}
}