Ding Wu, Hong Wang, De-Zhu Li, and Steven Blackmore (2005). "Pollen Morphology of Parnassia L. (Parnassiaceae) and Its Systematic Implications". Journal of Integrative Plant Biology47(1):2-12. doi:10.1111/j.1744-7909.2005.00008.x (see external links below).
Mark P. Simmons, Vincent Savolainen, Curtis C. Clevinger, Robert H. Archer, and Jerrold I. Davis (2001). "Phylogeny of Celastraceae Inferred from 26S Nuclear Ribosomal DNA, Phytochrome B, rbcL, atpB, and Morphology". Molecular Phylogenetics and Evolution19(3):353-366. doi:10.1006/mpev.2001.0937
