Valente, T.M. and C.L. Gomes. “The role of two acidophilic algae as ecological indicators of acid mine drainage sites”. Journal of Iberian Geology, vol. 33, vol. 33, no. 2, 2007, pp. 283-94, https://revistas.ucm.es/index.php/JIGE/article/view/JIGE0707210283A.