Mordechai Leuiken was a son of Abraham Leuiken and Alida Dias Santilhan. He married Betje Groenstad in Amsterdam on 16 September 1920, a daughter of Isaac Groenstad and Jansje Isaac van Bergen.
City Archive of Amsterdam, family registration card of Abraham Leuiken and website www.wiewaswie.nl .
In addition, a Jokos file (number 52644) on this family is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.