Artiom Alhazov Liudmila Burtseva Svetlana Cojocaru Yurii Rogozhin Solving PP-Complete and #P-Complete Problems by P Systems with Active Membranes. 108-117 2008 Workshop on Membrane Computing http://dx.doi.org/10.1007/978-3-540-95885-7_8 conf/membrane/2008 db/conf/membrane/membrane2008.html#AlhazovBCR08