@article{VM_2003_5_1_a4,
     author = {D. Weise},
     title = {The {Pythagorean} {Approach} to {Problems} of {Periodicity} in {Chemistry} and {Nuclear} {Physics}},
     journal = {Visual Mathematics},
     publisher = {mathdoc},
     volume = {5},
     number = {1},
     year = {2003},
     url = {http://geodesic.mathdoc.fr/item/VM_2003_5_1_a4/}
}