Henriette (Jettie) de Jong was married to Simon Fresco. He passed away in 1932. She was the daughter-in-law of Moses Fresco and Regina Frank. A picture of the Fresco-de Jong family can be found in: E. van Baarle, Vertrokken zonder nader adres: de joodse inwoners en onderduikers van Pijnacker, 1936 - 1945 (Pijnacker 2005).
In addition, a Jokos file (number 52103) on this family is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.