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Heijl A, Strahlman E, Sverrisson T, Brinchman-Hansen O, Puustjärvi T, Tipping R.Heijl A, et al. Among authors: sverrisson t.Ophthalmology. 1997 Jan;104(1):137-42. doi: 10.1016/s0161-6420(97)30348-0.Ophthalmology. 1997.PMID: 9022118Clinical Trial.