Alberto Leporati Claudio Zandron Miguel A. Gutiérrez-Naranjo P systems with input in binary form. 127-146 2006 17 Int. J. Found. Comput. Sci. 1 http://dx.doi.org/10.1142/S0129054106003735 db/journals/ijfcs/ijfcs17.html#LeporatiZG06