Prevalence of diabetic retinopathy in Norway: report from a screening study. - Kilstad, Hilde Nygaard; Sjølie, Anne Katrine; Gøransson, Lasse; Hapnes, Rune; Henschien, Hans Jørgen; Alsbirk, Knud Erik; Fossen, Kristian; Bertelsen, Geir; Holstad, Gro; Bergrem, Harald (Acta Ophthalmologica (1755375X), 2012)