db/journals/jacm/HenschenN84.html Lawrence J. Henschen Shamim A. Naqvi On compiling queries in recursive first-order databases. 47-85 1984 31 J. ACM 1 http://doi.acm.org/10.1145/2422.2423 db/journals/jacm/jacm31.html#HenschenN84 JACM/31/P0047.pdf