@article{VM_2006_8_4_a1,
     author = {M. C. Hess},
     title = {Binary {Symmetry}},
     journal = {Visual Mathematics},
     year = {2006},
     volume = {8},
     number = {4},
     url = {http://geodesic.mathdoc.fr/item/VM_2006_8_4_a1/}
}