Unsere geschichtliche Zukunft - Münster, Clemens. (OLS)http://ftis/name/79353; Guardini, Romano, 1885-1968. (OLS)http://ftis/name/51200; Krüger, Gerhard. (OLS)http://ftis/name/63187; Dirks, Walter. (OLS)http://ftis/name/56299 (Werkbund-Verlag,, 1954)