Doubell A. Hellmuth Friederich Heyderhoff Weich: 19/01/1937 - 14/4/2007. SAHJ [Internet]. 2017 Apr. 24 [cited 2026 Jun. 13];4(3):48-51. Available from: https://ngtt.journals.ac.za/index.php/SAHJ/article/view/2091