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.
Frits Klaarenbeek (1947). Tropenhelm, basis van gevlochten vezel waarover straalsgewijs vanaf de top elkaar overlappende brede vezelrepen genaaid, 1980. Europeana (aggregator, 4,000+ institutions).