1. Research Associate, Senior Research Associate, Senior Research Associate, and Professor of Toxicology, respectively, University Centre for Pharmacy, Department of Analytical Chemistry and Toxicology, Antonius Deusinglaan 2 NL-9713 AW Groningen NL.
2. Research Assistant, Senior Research Associate, and Research Assistant, respectively, Forensic Science Laboratory of Ministry of Justice, Rijswijk, NL.