H.J. van der Schroeff, 1938
Unknown author<span style="display: none;">Unknown author</span>
1938
De heer H. J. v. d. Schroeff,. "De Telegraaf". Amsterdam, 16-05-1938, p. 24. Geraadpleegd op Delpher op 19-09-2021, <a rel="nofollow" class="external free" href="https://resolver.kb.nl/resolve?urn=ddd:110578249:mpeg21:p004">https://resolver.kb.nl/resolve?urn=ddd:110578249:mpeg21:p004</a>