Edwards PET, Parsons GR, Myers KH. The economic value of viewing migratory shorebirds on the Delaware Bay: an application of the single-site travel cost model using on-site data. Hum Dimens Wildl. 2011;16(6):435-44. doi: 10.1080/10871209.2011.608180
Capdevila Bert R, Marsal Mora JR, Pujol Salud J, Anguera Farran R. Prevalence study of iodine deficiency in a 6-year-old school population. An Pediatr (Barc). 2010 May;72(5):331-8. doi: 10.1016/j.anpedi.2009.12.023