License, verbatimCC0
Museum Rotterdam, via Europeana: image published under Creative Commons Zero 1.0 (http://creativecommons.org/publicdomain/zero/1.0/). Rights statement as supplied by the contributing institution to Europeana.
Carl Denig. Beenkappen die met een band in de knieholte aangesloten zitten, met rits, 1930. Europeana (aggregator, 4,000+ institutions).