E. J. van Essen

Extradural clonidine does not potentiate analgesia produced by extradural morphine after meniscectomy.

J. Bovill, E. J. Ploeger, E. J. van Essen, 1991, British journal of anaesthesia.

Intrathecal morphine and clonidine for control of intractable cancer pain. A case report.

J. Bovill, H. Beerman, E. J. Ploeger, 1988, Acta anaesthesiologica Belgica.