Artiom Alhazov Rudolf Freund Alberto Leporati Marion Oswald Claudio Zandron (Tissue) P Systems with Unit Rules and Energy Assigned to Membranes. 391-408 2006 74 Fundam. Inform. 4 http://iospress.metapress.com/content/5v45rcedw5rfyvnv/ db/journals/fuin/fuin74.html#AlhazovFLOZ06