@article{ITA_2006__40_2_141_0,
     author = {Porreca, Antonio E. and Mauri, Giancarlo and Zandron, Claudio},
     title = {Complexity classes for membrane systems},
     journal = {RAIRO - Theoretical Informatics and Applications - Informatique Th\'eorique et Applications},
     pages = {141--162},
     publisher = {EDP-Sciences},
     volume = {40},
     number = {2},
     year = {2006},
     doi = {10.1051/ita:2006001},
     mrnumber = {2252633},
     zbl = {1112.68065},
     language = {en},
     url = {http://www.numdam.org/articles/10.1051/ita:2006001/}
}