1. 1. Rateitschak KH, Rateitschak EM, Wolf HF, Hassel TM (1989) Collor atlas of dental medicine 1. Periodontology. 2nd ed, Thieme Medical Publishers, New York, 311-313
2. 2. Yoneda M, Anan H, Motooka N, Hirofuji T, Matsumoto A, Isobe R, Kabashima H, Maeda K (2003) Disappearance of an external dental fistula with an endodontic treatment of the causative tooth. Nihon Shika Hozongaku Zasshi 46, 143-148 (in Japanese)
3. 3. Yoshie H, Hirose Y, Suzuki T, Hara K (1996) Relationship between peptidase activity from Treponema denticola, Porphyromonas gingivalis, and Bacteroides forsythus and attachment loss. Periodontal Clin Investig 18, 31-38
4. 4. Weine FS (1996) Endodontic Therapy. 5th ed, Mosby, St. Louis, 640-673
5. 5. Meng HX (1999) Periodontic-endodontic lesions. Ann Periodontol 4, 84-90