Wang, Wei; Lu, An-Ming; Ren, Yi; Endress, Mary E.; Chen, Zhi-Duan (2009). "Phylogeny and Classification of Ranunculales: Evidence from four molecular loci and morphological data". Perspectives in Plant Ecology, Evolution and Systematics. 11 (2): 81–110. doi:10.1016/j.ppees.2009.01.001.
Sang, Tao (1996). Phylogeny and Biogeography of Paeonia (PAEONIACEAE), dissertation. The Ohio State University. cited on"Tao Sang, DISSERTATION, chapter 4". Paeon. Retrieved 19 May 2016.