Jacob de Jong was a son of Abraham de Jong and Julie Waterman.
City Archive of Amsterdam, archive card of Jacob de Jong and Abraham de Jong.
In August 1941 Jacob de Jong was enrolled in the first year of the programme for fitters of the 3rd vocational school in East Amsterdam.
Data on Jewish students at Amsterdam vocational schools in 1941. Lists of Jewish students at vocational schools in Amsterdam appear in: A. Caransa, Van School Verwijderd. Jood. Dokumenten betreffende de verwijdering van joodse leerlingen van Amsterdamse ambachtsscholen in 1941 (Tuindorp z.d.).