V. P. Singh, A. S. Uppoor, D. G. Nayak, D. Shah: Black triangle dilemma and its management in esthetic dentistry. In: Dental research journal. Band 10, Nummer 3, Mai 2013, S. 296–301, PMID 24019795, PMC 3760350 (freier Volltext) (Review).
D. Cardaropoli, S. Re, G. Corrente: The Papilla Presence Index (PPI): a new system to assess interproximal papillary levels. In: The International journal of periodontics & restorative dentistry. Band 24, Nummer 5, Oktober 2004, S. 488–492, PMID 15506030.
