conf/pods/89 Pratul Dublish S. N. Maheshwari Expressibility of Bounded-Arity Fixed-Point Query Hierarchies. 324-335 1989 PODS db/conf/pods/pods89.html#DublishM89 http://doi.acm.org/10.1145/73721.73753 db/conf/pods/DublishM89.html journals/anthology/cd1-3:PODS89/P324.PDF journals/anthology/dvd1:text/1-3/PODS89/P324.PDF conf/popl/AhoU79 ... journals/jcss/ChandraH82 ... ... ... ... ... conf/focs/GurevichS85 journals/jcss/Immerman81 journals/iandc/Immerman86