TY - JOUR T1 - Modern Problems in Ophthalmology JF - British Journal of Ophthalmology JO - Br J Ophthalmol SP - 734 LP - 734 DO - 10.1136/bjo.61.11.734 VL - 61 IS - 11 AU - A. G. Chignell Y1 - 1977/11/01 UR - http://bjo.bmj.com/content/61/11/734.1.abstract N2 - 300 Multiple ChoicesThis is a pdf-only article and there is no markup to show you.full-text.pdf ER -