1. Schwartz, S, Shires, G, and Spencer, F. Principles of Surgery. 6th Ed: 1307–1318. New York, NY: McGraw-Hill, Inc., 1994.
2. Association of perforation of the appendix with female tubal infertility;Urbach;Am J Epidemiol,2001
3. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement;Moher;PLoS Med,2009
4. Wells G, Shea B, O'Connell D, Peterson J, Welch V, Losos M, Tugwell P. The Newcastle-Ottawa Scale (NOS) for assessing the quality of nonrandomised studies in meta-analyses. http://www.ohri.ca/programs/clinical_epidemiology/oxford.asp.
5. Meta-analysis in clinical trials;DerSimonian;Controlled Clin Trials,1986