title: Caudal additives to ropivacaine in children: preservative free S-ketamine versus clonidine
authors: Department of Anaesthesia and Intensive Care H 'Casa Sollievo della Sofferenza' IRCCS, S. Giovanni R, Italy; Children's Hospital 'Regina Margherita', Turin, Italy.
authors: De Negri P
authors: C
authors: Visconti
authors: G
authors: Ivani
authors: F
authors: Borrelli
authors: De Vivo P