@article {DBLP:journals/scp/PedreschiR03,
	title = {On logic programs that always succeed},
	journal = {Sci. Comput. Program.},
	volume = {48},
	number = {2-3},
	year = {2003},
	pages = {163-196},
	author = {Dino Pedreschi and Salvatore Ruggieri}
}
