1. Michaelson IC. Textbook of the Fundus of the Eye. London: Churchill Livingstone, 1980:19.
2. Hogan MJ, Alvarado JA, Weddell JE. Histology of the Human Eye: an Atlas and Textbook. Philadelphia, PA: Saunders, 1971.
3. Shimizu K. Fluorescein Microangiography of the Ocular Fundus. Tokyo: Igaku Shoin, 1973.
4. Macular-foveal capillaries in human retina;Yeung;Aust J Ophthalmol,1973
5. Capillary-free area of the fovea with advancing age;Laatikainen;Invest Ophthalmol Vis Sci,1977