<http://schema.org/item>
<http://chemwiki.ucdavis.edu/Physical_Chemistry/Quantum_Mechanics/11%3A_Molecules>
<http://chemwiki.ucdavis.edu/Physical_Chemistry/Quantum_Mechanics/11%3A_Molecules/Virtual%3A_Molecular_Orbitals/Overlap_of_Atomic_Orbitals>