Effect of intravenous low‐dose S‐ketamine on pain in patients with Complex Regional Pain Syndrome: A retrospective cohort study. - Mangnus, Thomas J. P.; Dirckx, Maaike; Bharwani, Krishna D.; de Vos, Cecile C.; Frankema, Sander P. G.; Stronks, Dirk L.; Huygen, Frank J. P. M. (Pain Practice, 2021)