Attribution-Share Alike 2.0 truetrue 19 August 2010 et:Anton van Berkel nl:Anton van Berkel English author name string: Steenslag determination method: SHA-1
https://creativecommons.org/licenses/by/3.0CC BY 3.0 Creative Commons Attribution 3.0 truetrue English Ben van Berkel, 2017 determination method: SHA-1