Rodrigues, Sónia Sofia S., Carla Sofia S. Ferreira, y Paulo C. Silveira. «An historical survey of the botanical research done at the Lousã mountain system (Portugal)». Botanica Complutensis, vol. 29, vol. 29, 2005, pp. 35-42, https://revistas.ucm.es/index.php/BOCM/article/view/BOCM0505110035A.