@book{177109,
	author = {Luhmann, Niklas},
	title = {Sociedad y sistema},
	publisher = {Ediciones Paidós},
	year = {c1990.},
	series = {Pensamiento contemporáneo},
	address = {Barcelona},
	edition = {1a ed.},
	note = {Translation of the chapter I of: Soziale systeme.}
}