Anijeet, Deepa Endonasal versus external dacryocystorhinostomy for nasolacrimal duct obstruction. [electronic resource] - The Cochrane database of systematic reviews Jan 2011 - CD007097 p. digital Publication Type: Journal Article; Review; Systematic Review ISSN: 1469-493X Standard No.: 10.1002/14651858.CD007097.pub2 doi Subjects--Topical Terms: Dacryocystorhinostomy--methodsHumansRandomized Controlled Trials as TopicTreatment Failure