Artiom Alhazov Alexander Krassovitskiy Yurii Rogozhin Sergey Verlan P Systems with Insertion and Deletion Exo-Operations. 13-28 2011 110 Fundam. Inform. 1-4 http://dx.doi.org/10.3233/FI-2011-525 db/journals/fuin/fuin110.html#AlhazovKRV11