@article{VM_2008_10_4_a0,
     author = {J. C. Perez},
     title = {Symmetry and {Asymmetry} in the {Mendele{\"\i}ev's} {Periodic} {Table} {Predictive} {Equation}},
     journal = {Visual Mathematics},
     publisher = {mathdoc},
     volume = {10},
     number = {4},
     year = {2008},
     url = {http://geodesic.mathdoc.fr/item/VM_2008_10_4_a0/}
}