"Cohen, David (1882-1967)". Biografisch Woordenboek van Nederland 3 (Den Haag 1989) (in Dutch). 2015-01-12. Archived from the original on 2021-08-09. Retrieved 2021-08-09.
"Cohen, David (1882-1967)". Biografisch Woordenboek van Nederland 3 (Den Haag 1989) (in Dutch). 2015-01-12. Archived from the original on 2021-08-09. Retrieved 2021-08-09.