@article {643,
	title = {First Steps Towards Linking Membrane Depth and the Polynomial Hierarchy},
	journal = {Eighth Brainstorming  Week on Membrane Computing},
	year = {2010},
	month = {02/2010},
	pages = {255-266},
	publisher = {F{\'e}nix Editora},
	address = {Sevilla, Spain},
	isbn = {978-84-614-2357-6},
	url = {http://www.gcn.us.es/8BWMC/volume/20polyheir.pdf},
	attachments = {http://www.gcn.us.es/biblio/author/files/20polyheir.pdf},
	author = {Niall Murphy and Antonio E. Porreca}
}
