When copying data from this family tree, please include a reference to the origin: Jaap van der Werff, "Family tree Van der Werff / Kooistra", database, Genealogy Online (https://www.genealogieonline.nl/van-der-werff-stamboom/I511336.php : accessed May 17, 2024), "Albert Arents Calsbeek (1746-????)".
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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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