1. Pauling L (1940) The nature of the chemical bond. Cornell University Press, Ithaca, New York
2. Van Vleck JH (1932) The theory of electric and magnetic susceptibilities. University Press, Oxford
3. Numerically exact computations for the ground state of the VB model have been performed for systems having up to 24 sites: Alexander SA, Schmalz TG, J Am Chem Soc (submitted)
4. Numerically exact computations for the ground state of the VB model have been performed for systems having up to 24 sites: see also, Ramasesha S, Soos ZG (1984) Int J Quantum Chem 25:1003
5. The special case of the ground state of a cyclic chain without bond-alternation turns out to be exactly soluble by a complex many-body technique which has not been extended to other structures: Hulthen L (1938) Ark Mat Astron Fys A26:1