@inbook {ICEsSi90b,
	title = {On the Analysis and Synthesis of Free Choice Systems},
	booktitle = {Advances in Petri Nets 90},
	volume = {483},
	year = {1991},
	pages = {243-286},
	publisher = {Springer-Verlag},
	organization = {Springer-Verlag},
	address = {Berlin},
	author = {J. Esparza and M. Silva},
	editor = {G. Rozenberg}
}

