@article{VM_1999_1_3_a5,
     author = {Ana Kozomara},
     title = {Discrete {Plane} {Symmetry} {Groups}},
     journal = {Visual Mathematics},
     publisher = {mathdoc},
     volume = {1},
     number = {3},
     year = {1999},
     url = {http://geodesic.mathdoc.fr/item/VM_1999_1_3_a5/}
}