@article {545,
	title = {On Sigma-n definability in Arithmetic.},
	journal = {Philosophical Dimensions of Logic and Science},
	year = {2003},
	pages = {47-56},
	publisher = {Springer},
	edition = {1},
	chapter = {4},
	isbn = {978-1402016455},
	url = {http://www.cs.us.es/~marper/investigacion/definab.pdf},
	attachments = {http://www.gcn.us.es/biblio/q=node/modules/files/definab.pdf},
	author = {Joaqu{\'\i}n Borrego-D{\'\i}az and Alejandro Fern{\'a}ndez-Margarit and Mario J. P{\'e}rez-Jim{\'e}nez},
	editor = {A. Rojszczak and J. Cachro and G. Kurczewski}
}
