1. Agapito, D., Mendes, J., & do Valle, P. O. (2012). The rural village as an open door to nature-based tourism in Portugal: the Aldeia da Pedralva case. Tourism, 60(3), 325–338.
2. Benassayag, C., Perrot-Applanat, M., & Ferre, F. (2002). Phytoestrogens as modulators of steroid action in target cells. Journal of Chromatography B, 777(1–2), 233–248. doi: 10.1016/S1570-0232(02)00340-9 .
3. Bettencourt, A.M., Bricker, S.B., Ferreira, J.G., Franco, A., Marques, J.C., Melo, J.J., et al. (2003). Typology and reference conditions for Portuguese transitional and coastal waters. Development of guidelines for the application of the European Union Water Framework Directive. INAG – Instituto da Água, 1–119.
4. Caldwell, D. J., Mastrocco, F., Anderson, P. D., Lange, R., & Sumpter, J. P. (2012). Predicted-no-effect concentrations for the steroid estrogens estrone, 17beta-estradiol, estriol, and 17alpha-ethinylestradiol. Environmental Toxicology and Chemistry, 31(6), 1396–1406.
5. Chainho, P., Chaves, M. L., Costa, J. L., Costa, M. J., & Dauer, D. M. (2008). Use of multimetric indices to classify estuaries with different hydromorphological characteristics and different levels of human pressure. Marine Pollution Bulletin, 56(6), 1128–1137. doi: 10.1016/j.marpolbul.2008.03.018 .