Elias Roeper was the son of Emanuel Roeper and Schoontje Peper. he married Elisabeth Korper in 1920. She was the daughter of David Korper and Rebecca Kokernoot.
Amsterdam Municipal Archives; record card of Elias Roeper
In addition, a Jokos file (number 2125) on this family is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.