Yousefi, Z., Negaresh, K. and Kaya, Y. 2021. A taxonomic study on Psephellus sect. Amblyopogon (Asteraceae, Cardueae—Centaureinae). Phytotaxa. 494, 3 (Apr. 2021), 273–288. DOI:https://doi.org/10.11646/phytotaxa.494.3.3.