https://www.joodsmonument.nl/nl/page/181756/duifje-heertje-halmans
https://levie-kanes.com/humogen/family.php?database=humo_&id=F15921&main_person=I44662
See for more links:
[CLI Part 27] do_MAxzEPXjrLrJNtzyqSBQs Duifje Heertje-Halmans - Dokumente - Talk in the Forum of the Arolsen Archives (arolsen-archives.org)