Corrigendum: Different pharmacokinetics of tramadol, O-demethyltramadol and N-demethyltramadol in postoperative surgical patients from those observed in medical patients - Neskovic, Nenad; Mandic, Dario; Marczi, Saska; Skiljic, Sonja; Kristek, Gordana; Vinkovic, Hrvoje; Mraovic, Boris; Debeljak, Zeljko; Kvolik, Slavica (Frontiers in Pharmacology, 2023)