H. H. Russ, “Ocular surface evaluation in patients treated with a fixed combination of prostaglandin analogues with 0.5% timolol maleate topical monotherapy: a randomized clinical trial”, Clinics, vol. 68, no. 10, pp. 1318–1324, Oct. 2013, doi: 10.1590/clin.v68i10.77008.