A recent collection of papers on concurrent object systems is [Agha et al., 1993]. Various languages have been proposed that marry aspects of object-based systems with aspects of Shoham's agent-oriented proposal. Two examples are AGENTSPEAK and DAISY. AGENTSPEAK is loosely based on the PRS agent architecture, and incorporates aspects of concurrent-object technology [Weerasooriya et al., 1994]. In contrast, DAISY is based on the concurrent-object language CUBL ([Adorni and Poggi, 1993]), and incorporates aspects of the agent-oriented proposal [Poggi, 1994].
Other languages of interest include OZ [Henz et al., 1993] and IC PROLOG II [Chu, 1993]. The latter, as its name suggests, is an extension of PROLOG, which includes multiple-threads, high-level communication primitives, and some object-oriented features.