@book{11178,
	author = {Gabriel, Peter and Zisman, Michel and Zisman, Michel},
	title = {Calculus of fractions and homotopy theory},
	publisher = {Springer-Verlag,},
	year = {1967},
	series = {Ergebnisse der Mathematik und ihrer Grenzgebiete},
	address = {New York:}
}