@article{TR98,
	author = {Daniele Turi and Jan Rutten},
	title = {On the foundations of final coalgebra semantics:
		  non-well-founded sets, partial orders, metric spaces},
	year = {1998},
        journal = "Mathematical Structures in Computer Science",
        volume = "8",
        number = "5",
        pages = "481-540",
        source = {http://www.dcs.ed.ac.uk/home/dt/}
		  }