DEGAS: Capturing Dynamics in Objects. - Johan van den Akker; Arno Siebes (CAiSE, 1996)

Object Histories as a Foundation for an Active OODB. - Johan van den Akker; Arno Siebes (DEXA Workshop, 1996)

Enriching Active Databases with Agent Technology. - Johan van den Akker; Arno Siebes (CIA, 1997)

DEGAS: A Database of Autonomous Objects. - Johan van den Akker; Arno Siebes (Inf. Syst., 1997)