Levene, J. R. (1966). „Sir George Biddell Airy, F.R.S. (1801-1892) and the Discovery and Correction of Astigmatism“. Notes and Records of the Royal Society of London. 21 (2): 180–199. doi:10.1098/rsnr.1966.0017. JSTOR531067.
Read, Scott A; Collins, Michael J; Carney, Leo G (2007). „A review of astigmatism and its possible genesis“. Clinical and Experimental Optometry. 90 (1): 5–19. doi:10.1111/j.1444-0938.2007.00112.x. PMID17177660.
Levene, J. R. (1966). „Sir George Biddell Airy, F.R.S. (1801-1892) and the Discovery and Correction of Astigmatism“. Notes and Records of the Royal Society of London. 21 (2): 180–199. doi:10.1098/rsnr.1966.0017. JSTOR531067.
Read, Scott A; Collins, Michael J; Carney, Leo G (2007). „A review of astigmatism and its possible genesis“. Clinical and Experimental Optometry. 90 (1): 5–19. doi:10.1111/j.1444-0938.2007.00112.x. PMID17177660.