@article {,
	title = {On the Power of P systems with Valuation},
	journal = {Computaci{\'o}n y Sistemas. Revista Iberoamericana de Inteligencia Artificial},
	volume = {5},
	year = {2002},
	pages = {120-127},
	address = {Mexico Ciudad},
	issn = {0166-218X},
	author = {Carlos Mart{\'\i}n-Vide and Victor Mitrana and Gheorghe Paun}
}
