Ingrid Biehl Bernd Meyer Susanne Wetzel Ensuring the Integrity of Agent-Based Computations by Short Proofs. 183-194 1998 conf/ma/1998 Mobile Agents http://link.springer.de/link/service/series/0558/bibs/1477/14770183.htm db/conf/ma/ma1998.html#BiehlMW98