RT Journal Article SR Electronic T1 Prospective randomised comparison of external dacryocystorhinostomy with and without silicone intubation: considerations of power JF British Journal of Ophthalmology JO Br J Ophthalmol FD BMJ Publishing Group Ltd. SP 151 OP 152 DO 10.1136/bjo.2009.173286 VO 95 IS 1 A1 S Dulku A1 A Murray A1 O M Durrani YR 2011 UL http://bjo.bmj.com/content/95/1/151.abstract AB