Fekroune Chaker, A. “Usnea Cornuta Körb. And Usnea Glabrescens (Vainio) Vainio Sens. Lat.: Species to Be Protected in the Peninsula of Edough (Algeria)”. Cellular and Molecular Biology, vol. 62, no. 6, May 2016, pp. 69-73, https://www.cellmolbiol.org/index.php/CMB/article/view/875.