Kenneth J. Sytsma, Jeffery Morawetz, J. Chris Pires, Molly Nepokroeff, Elena Conti, Michelle Zjhra, Jocelyn C. Hall, and Mark W. Chase. (2002). Urticalean rosids: Circumscription, rosid ancestry, and phylogenetics based on rbcL, trnL-F, and ndhF sequences. American Journal of Botany89(9): 1531-1546. PDF fulltext