9Karim R,Ghabrial R,Lynch T,et al.A comparison of external and endoscopic endonasal dacryocystorhinostomy for acquired nasolacrimal duct obstruction[J].Clin Ophthalmol, 2011 (5):979-989.
10SongHY, Lee DH, Ahn HS, et al. Lacrimal system obstruction treated with lacrimal polyurethane stents: outcome of removal of occluded stents[J]. Radiology, 1998, 208(3):689-694.