Albert Atserias Maria Luisa Bonet On the Automatizability of Resolution and Related Propositional Proof Systems Electronic Colloquium on Computational Complexity (ECCC) 2002 010 db/journals/eccc/eccc9.html#ECCC-TR02-010 http://eccc.hpi-web.de/eccc-reports/2002/TR02-010/index.html