@book{14779,
	author = {Szego, G. P. and Treccani, G. and Treccani, G. ; jt. auth.},
	title = {Semigruppi di transformazioni multivoche},
	publisher = {Springer-Verlag},
	year = {1969},
	series = {Lecture notes in Mathematics},
	address = {Berlin}
}