1. https://it.wikipedia.org/wiki/Diamante.
2. https://it.wikipedia.org/wiki/Allotropia_%28chimica%29#/media/File:Diamond_and_graphite.jpg.
3. The Physics of Fullerene-Based and Fullerene-Related Materials;Andreoni,2000
4. Superaromaticity;Osawa;Kagaku (Kyoto),1970
5. Aromaticity. Chemical Monograph Series 22;Yoshida,1971