J. A.  Pedersen, ?Distribution and taxonomic implications of some phenolics in the family Lamiaceae determined by ESR spectroscopy?, Biochem Syst Ecol, vol. 28. pp. 229?253, 2000.

G.  Janicsak, Veres, K., Kakasy, A. Z., and Mathe, I., ?Study of the oleanolic and ursolic acid contents of some species of the Lamiaceae?, Biochem Syst Ecol, vol. 34, pp. 392?396, 2006.