4Maddalone M, Gagliani M. Periapical endodontic surgery: a 3-year follow-up study. Int Endodo J, 2003, 36(3): 193-198,.
5Friedman S. Retrograde approaches in endodontic therapy. Endo- dontics and Dental Traumatology, 1991, 7(3): 97-107.
6Moiseiwitsch J, Trope M. Nonsurgical root canal therapy treatment with apparent indications for root-end surgery. Oral Surg Oral Med Oral Pathol Oral Radiol Endod, 1998, 86(3): 335-340.
7Frew AJ. 25 Immunotherapy of allergic disease, J Allergy Clin Immu- nol, 2003, 111(2 Suppl): S712-719.
8Deeks JJ, Dinnes J, D'Amico R, et al. Evaluating non-randomised intervention studies. Health Technol Assess, 2003, 7(27): 170-173.
9Tsesis I, Rosen E, Schwartz-Arad D, et al. Retrospective evaluation of surgical endodontic treatment: traditional versus modern tech- nique. J Endod, 2006, 32(5): 412-416.
10Testori T, Capelli M, Milani S, et al. Success and failure inperiradic- ular surgery:a longitudinal retrospective analysis. Oral Surg Oral Med Oral Pathol Oral Radiol Endod, 1999, 87(4): 493-498.