Nota in calce

b Vedi The Journal of Thoracic and Cardiovascular Surgery, vol. 134, n. 2, pp. 287-288; Texas Heart Institute Journal, vol. 38, n. 5, p. 563; Basics of Blood Management, p. 2 e Continuing Education in Anaesthesia, Critical Care & Pain, vol. 4, n. 2, p. 39.