Henry de Jonge was a son of Benjamin de Jonge and Sara de Levie, who both are mentioned in the Gedenkbuch.
Stadsarchief Amsterdam, archiefkaart Henry de Jonge
See H. P. Klausch, Jakob de Jonge. Aus deutschen Konzentrationslagern in den niederländischen Untergrund (Bremen 2002) for his role in the resistance at the start of nazism in Germany when he still lived in Weener, the city of his birth (see page 26 note 93, page 56 note 222).