"Volk", "Bevölkerung", "Rasse", and "Raum" : Erich Keyser's Ambiguous Concept of a German History of Population, ca. 1918-1955 - Pinwinkler, Alexander (. German scholars and ethnic cleansing. - New York [u.a.] : Berghahn Books, 2005. - XXI, 298 Seiten. - ISBN 1-571-81435-3, 2005)