Jan Johannsen Lower Bounds for Monotone Real Circuit Depth and Formula Size and Tree-like Cutting Planes Electronic Colloquium on Computational Complexity (ECCC) 1997 32 4 db/journals/eccc/eccc4.html#ECCC-TR97-032 http://eccc.hpi-web.de/eccc-reports/1997/TR97-032/index.html