Iranzo, J., et al. “. (PDF) Contributions to the Knowledge of the Genus Equisetum L. II. E. X Litorale Rupr”. Acta Botanica Malacitana, vol. 11, Dec. 1986, pp. 147-56, https://doi.org/10.24310/Actabotanicaabmabm.v11i.9465.