Ismail, Rizgar Y., and Saleem E. Shahbaz. “Use of Pollen Morphology Traits for Identifying Species of Centaurea L. Asteraceae in Kurdistan-Iraq”. Science Journal of University of Zakho, vol. 8, no. 4, Dec. 2020, pp. 131-8, https://doi.org/10.25271/sjuoz.2020.8.4.754.