Roberto Barbuti Andrea Maggiolo-Schettini Paolo Milazzo Angelo Troina The Calculus of Looping Sequences for Modeling Biological Membranes. 54-76 2007 conf/membrane/2007 Workshop on Membrane Computing http://dx.doi.org/10.1007/978-3-540-77312-2_4 db/conf/membrane/membrane2007.html#BarbutiMMT07