M. Oswald:
"Computations with 1-deterministic P Systems Using Antiport/Symport Rules for Evolution Rules";
WSEAS Transactions on Biology and Biomedicine, 2 (2004), 1; 280 - 286.
http://aleph.ub.tuwien.ac.at/F?base=tuw01&func=find-c&ccl_term=AC04968497