Shock-wave lithotripsy of gallbladder stones. The first 175 patients - Sackmann, M; Delius, M; Sauerbruch, T; Holl, J; Weber, W; Ippisch, E; Hagelauer, U; Wess, O; Hepp, W; Brendel, W; Paumgartner, G. (New Engl J Med, 1988)