Quedensley, T. S., M. Gruenstaeudl, and R. K. Jansen. “Phylogenetic Relationships of the Mexican Tussilaginoid Genera (Asteraceae: Senecioneae)”. Journal of the Botanical Research Institute of Texas, Vol. 12, no. 2, Nov. 2018, pp. 481-98, https://journals.brit.org/jbrit/article/view/951.