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Hussain, Badrul; Saleh, George M; Sivaprasad, Sobha; Hammond, Christopher J (2006). "Changing from Snellen to LogMAR: debate or delay?". Clinical and Experimental Ophthalmology. 34 (1): 6–8. doi:10.1111/j.1442-9071.2006.01135.x. PMID16451251. S2CID44724633.
Hussain, Badrul; Saleh, George M; Sivaprasad, Sobha; Hammond, Christopher J (2006). "Changing from Snellen to LogMAR: debate or delay?". Clinical and Experimental Ophthalmology. 34 (1): 6–8. doi:10.1111/j.1442-9071.2006.01135.x. PMID16451251. S2CID44724633.