López, E., & Devesa, J. A. (2008). Taxonomic notes on genus Centaurea L. (Asteraceae) in the Iberian Peninsula. I. C. cordubensis Font Quer, C. bethurica E. López & Devesa, sp. Nov., and C. schousboei Lange. Anales Del Jardín Botánico De Madrid, 65(2), 331–341. https://doi.org/10.3989/ajbm.2008.v65.i2.296