Pring CM, Skelding-Millar L, Goodall RJ. Expectant treatment or cholecystectomy after endoscopic retrograde cholangiopancreatography for choledocholithiasis in patients over 80 years old? Surg Endosc. 2005 Mar;19(3):357-60.
López MV, Rivero E, Serra C, Campo M, Raurich M, Bonfill X. Health survey in health care professionals in Barcelona. Arch Prev Riesgos Laborales. 1998;1(2):55-62.