Cardona, M., Colomer A. M., Margalida A., Pérez-Hurtado I., Pérez-Jiménez M. J., & Sanuy D.  (2009).??A P system based model of an ecosystem of some scavenger birds.  (Gheorghe Paun, Mario J. Pérez-Jiménez, Agustín Riscos-Núñez, Ed.).10th Workshop on Membrane Computing.  153-168.