Hitoshi Ohsaki Hiroyuki Seki Toshinori Takai Recognizing Boolean Closed A-Tree Languages with Membership Conditional Rewriting Mechanism. 483-498 2003 conf/rta/2003 RTA http://link.springer.de/link/service/series/0558/bibs/2706/27060483.htm db/conf/rta/rta2003.html#OhsakiST03