In the Nederlandsch Tijdschrift voor Tandheelkunde (1946), a list of dentists killed in the war appears on pp. 118-119. Martha Schaap-Simons was among them.
In addition, a Jokos file (number 6345) on this family is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.