Neftalie van Os was the son of Joseph van Os and Vogeline de Rosa. He was married to Rachel Wertheijm. They had no children. The couple lived at 14 Carillonstraat, fourth floor, in Amsterdam.
NIOD, Records Stichting Sieraden-Comité, box HF 15, file 225
In addition, a Jokos file (number 8642) on this family is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.