@article{TM2_2007_X_1_a0,
     author = {Ivan Gutman},
     title = {Hexagonal systems. a chemistry-motivated excursion to combinatorial geometry},
     journal = {The Teaching of Mathematics},
     pages = {1 },
     publisher = {mathdoc},
     volume = {X},
     number = {1},
     year = {2007},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/TM2_2007_X_1_a0/}
}