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
Ribeiro-Oliveira Jr A, Mol SS, Twiss J, Alencar GA, Miranda PA, Naves LA, Azevedo MF, Basilio FM, Boguszewski CL, Nogueira KC, Vilar L, Koltowska-Haggstrom M, McKenna SP. The brazilian version of the Quality of Life Assessment of Growth Hormone Deficiency in Adults (QoL-AGHDA): four-stage translation and validation. Arq Bras Endocrinol Metabol. 2010 Dec;54(9):833-41.