title: naos - efficient and modular reactive capabilities in an object-oriented database system. authors: thierry coupaye , t. svensen , christine collet. venue: vldb. year: 1994
title: the ccube constraint object-oriented database system. authors: alexander brodsky , victor e. segal , jia chen , paval a. exarkhopoulo. venue: international conference on management of data. year: 1999