H. A. Sánchez Montaña, L. M. Rodríguez Cely, and Y. C. Delgado Solarte, “Concordance between astigmatism values obtained using Javal’s rule and subjective refraction”., svo, vol. 14, no. 2, pp. 61–70, Jan. 2016, doi: 10.19052/sv.3838.