When copying data from this family tree, please include a reference to the origin: J. Ham, "Family tree Ham", database, Genealogy Online (https://www.genealogieonline.nl/stamboom-ham/I76579.php : accessed January 10, 2026), "Derk Willem Onstein (± 1861-????)".
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Please stick to the following rules
Request permission to copy data or at least inform the author, chances are that the author gives permission, often the contact also leads to more exchange of data.
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