Gascon M, Cirach M, Martinez D, Dadvand P, Valentin A, Plasencia A, Nieuwenhuijsen MJ. Normalized difference vegetation index (NDVI) as a marker of surrounding greenness in epidemiological studies: the case of Barcelona city. Urban For Urban Green. 2016 Sep;19:88-94. doi: 10.1016/j.ufug.2016.07.001
Fleming A, Goatman KA, Sharp PF, Styles CJ, Wikes WN, Olson JA. A large scale validation of automated grading. Eur J Ophthalmol. 2009 May 1;19(3):504.