RT Journal Article SR Electronic T1 Trabeculectomy with fistula formation in the African. JF British Journal of Ophthalmology JO Br J Ophthalmol FD BMJ Publishing Group Ltd. SP 32 OP 36 DO 10.1136/bjo.56.1.32 VO 56 IS 1 A1 N H Welsh YR 1972 UL http://bjo.bmj.com/content/56/1/32.abstract AB