Template:Ackerfield & al. 2020
- Ackerfield, J., Keil, D.J., Hodgson, W.C., Simmons, M.P., Fehlberg, S.D. & Funk, V.A. 2020. Thistle be a mess: Untangling the taxonomy of Cirsium (Cardueae: Compositae) in North America. Journal of Systematics and Evolution 58: 881-912. DOI: 10.1111/jse.12692
