Jacob van Emrik was a son of Simon van Emrik and Grietje van Cleef. He married in Amsterdam on 6 November 1935 to Margaretha Worms. City Archive of Amsterdam, archive card of Simon van Emrik.
In addition, a Jokos file (number 001999) on this family is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.