Shamim A. Naqvi Tomasz Imielinski Madhur Kohli Kumar V. Vadaparty Speculative Query Evaluation over Databases of Plans. 439-450 CIKM1993/P439.pdf 1993 conf/cikm/93 CIKM db/conf/cikm/cikm93.html#NaqviIKV93 http://doi.acm.org/10.1145/170088.170391