Kenneth J. Wurdack; Charles C. Davis (2009), "Malpighiales phylogenetics: Gaining ground on one of the most recalcitrant clades in the angiosperm tree of life", American Journal of Botany, 96 (8): 1551–1570, doi:10.3732/ajb.0800207, PMID21628300, S2CID23284896
Kenneth J. Wurdack; Charles C. Davis (2009), "Malpighiales phylogenetics: Gaining ground on one of the most recalcitrant clades in the angiosperm tree of life", American Journal of Botany, 96 (8): 1551–1570, doi:10.3732/ajb.0800207, PMID21628300, S2CID23284896
nccih.nih.gov
"St. John's Wort". National Center for Complementary and Integrative Health, US National Institutes of Health. September 2016. Retrieved 17 June 2018.
Kenneth J. Wurdack; Charles C. Davis (2009), "Malpighiales phylogenetics: Gaining ground on one of the most recalcitrant clades in the angiosperm tree of life", American Journal of Botany, 96 (8): 1551–1570, doi:10.3732/ajb.0800207, PMID21628300, S2CID23284896