Chen Rongsi, S. J. Cyvin, B. N. Cyvin, J. Brunvoll, D. J. Klein,
Methods of enumerating Kekulé structures, exemplified by applications to rectangle-shaped benzenoids Topics in Current Chemistry. ,vol. 153, pp. 227- 253 ,(1990) ,
10.1007/3-540-51505-4_26