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
Franzini L, White C, Taychakhoonavudh S, Parikh R, Zezza M, Mikhail O. Variation in inpatient hospital prices and outpatient service quantities drive geographic differences in private spending in Texas. Health Serv Res. 2014 Dec;49(6):1944-63. doi: 10.1111/1475-6773.12192