1Young JW, Ginthner TP, Keramati BK. The competitive bari- um meal[ J ]. Clinical Radiology, 1985,36:43.
2Stein GN, Martin. R, Roy RH, et al. Evaluation of conven- tional rorntgenographic techniques for demonstration of duo- denal ulcer craters [ J ]. A JR, 1964,91 : 801.