1. Senior Research Associate of the Institute of Clinical Pharmacology, Institute of Clinical Experimental Anesthesiology of the State University of Groningen and of the Catholic University Hospital of Nijmegen.
2. Professor of Anesthesia, Catholic University Hospital of Nijmegen.
3. Technical Research Associate of the Institute of Clinical Experimental Anesthesiology, University Hospital of Groningen.
4. Senior Research Associate of the Institute of Pharmacology of the State University of Groningen.