References
For Cyanus
Boršić, I., A. Susanna, S. Bancheva, and N. Garcia-Jacas. 2011. Centaurea sect. Cyanus: nuclear phylogeny, biogeography, and life-form evolution. Int. J. Plant Sci. 172: 238-249. Google Scholar
Cronquist, A. 1980. Asteraceae, Volume I, Vascular flora of the Southeastern United States. University of North Carolina Press, Chapel Hill, N.C. Google Scholar
Greuter, W., G. Wagenitz, M. Agababian, and F.H. Hellwig. 2001. (1509) Proposal to conserve the name Centaurea (Compositae) with a conserved type. Taxon 50: 1201-1205. Google Scholar
Keil, D.J., and J. Ochsmann. 2006. Centaurea. In Flora of North America Editorial Committee. 2006a. Flora of North America north of Mexico. Volume 19, Magnoliophyta: Asteridae, part 6: Asteraceae, part 1. Oxford Univ. Press, New York, NY. 579 pp. Google Scholar
Negaresh, K. 2018. A new combination in the genus Cyanus (Asteraceae: Cardueae, Centaureinae). Candollea 73: 101-103. Google Scholar