M. B. Crespo, M. A. Alonso, M. Martínez-Azorín, A. Vicente, J. L. Villar, and M. Chambouleyron, “New data on the recently described Xiphion heracleanum (Iridaceae), endemic to Morocco”, Phytotaxa, vol. 162, no. 1, pp. 31–43, Mar. 2014.