R. Freund, A. Alhazov, S. Ivanov:
"Transitional P Systems with Randomized Rule Right-hand Sides.";
in: "Preproceedings of the 18th Conference on Membrane Computing, CMC18, Bradford", M. Gheorghe et al. (ed.); IMCS, Bradford, 2017, 23 - 47.
http://publik.tuwien.ac.at/files/publik_263917.pdf