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://dx.doi.org/10.1007/3-540-44881-0_34 db/conf/rta/rta2003.html#OhsakiST03