Gerd Lange was a student at the School of the Jewish Community (Volksschule der Jüdischen Gemeinde) at Rykestr. 53 in Berlin Prenzlauer Berg prior to emigrating to Holland in the late 1930s. (Gedenkbuch Berlins, Berliner Adreßbuch)
In addition, a Jokos file (number 50563) on this family is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.