R. Freund, G. Paun, G. Rozenberg, and A. Salomaa. DNA Based Computers, volume 48 of DIMACS Series in Discrete Mathematics and Theoretical Computer Science, page 297-327. DIMACS/AMS, (1997)
J. Kleijn, M. Koutny, and G. Rozenberg. Workshop on Membrane Computing, volume 3850 of Lecture Notes in Computer Science, page 292-309. Springer, (2005)