1[1]Miller RE. The technical approach to the acute abdomen[J]. Semin Roentgenol,1973,8(1):267-279.
2[2]Markowitz SK, Ziter FMH Jr. The lateral chest film and pneumoperito-neum[J]. Ann Emerg Med, 1986,15(2):425-427.
3[3]Miller RE, Nelson SW. The roentgenologic demonstration of tiny amounts of free intraperitoneal gas: experimental and clinical studies[J]. AJR,1971,112(3):574-585.
4[4]Stapakis JC, Thickman D. Diagnosis of pneumoperitoneum: abdominal CT vs upright chest fiIm[J]. J Comput Assist Tomogr, 1992,16(4):713-716.
5[5]Levine MS, Scheiner JD, Rubesin SE, et al. Diagnosis of pneumoperium on supine abdominal radinographs[J]. AJR,1991,156(4):731-735.