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
Kjeldsen BJ, Thorsen H, Whalley D, Kronborg O. Influence of follow-up on health-related quality of life after radical surgery for colorectal cancer. Scand J Gastroenterol. 1999 May;34(5):509-15.