Bayer AM, Danysh HE, Garvich M, Gonzalvez G, Checkley W, Alvarez M, Gilman RH. An unforgettable event: a qualitative study of the 1997-98 El Niño in northern Peru. Disasters. 2014 Apr;38(2):351-74. doi: 10.1111/disa.12046
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.