Holl, Karl, 1866-1926 (Personal Name)
Enthusiasmus und Bussgewalt beim griechischen Mönchtum, 1898: title page (von Karl Holl)
Fragmente vornicänischer Kirchenväter, 1899: title page (aus den Sacra parallela herausgegeben von Karl Holl)
Deutsche Nationalbibliothek online catalog, viewed March 18, 2014 (authorized access point: Holl, Karl; other data in authority record: professor; born 1866 in Tübingen; died 1926 in Berlin)
Bibliothèque nationale de France online catalog, viewed March 18, 2014 (Holl, Karl; born 15 May 1866; died 23 May 1926; Protestant theologian and church historian; philologist)
German Wikipedia, viewed June 7, 2018 (Karl Holl (Theologe); Karl Holl; born May 15, 1866, in Tübingen; died May 23, 1926, in Berlin; professor of theology and church history in Tübingen und Berlin; published widely on Martin Luther and on the Greek fathers of the church)