RT Journal Article SR Electronic T1 Studies in the Aetiology of Pterygium: Part 1—Pinguecula and Pterygium in Caucasians in Singapore JF Journal of the Royal Army Medical Corps JO J R Army Med Corps FD British Medical Journal Publishing Group SP 117 OP 121 DO 10.1136/jramc-116-03-02 VO 116 IS 3 A1 R. M. Youngson YR 1970 UL http://militaryhealth.bmj.com/content/116/3/117.abstract AB