S. J.  WAGSTAFF, OLMSTEAD, R. G., and CANTINO, P. D., ?Parsimony Analysis of cpDNA Restriction Site Variation in Subfamily Nepetoideae (Labiatae)?, Am J Bot, vol. 82, pp. 886?892, 1995.

O.  Ryding, ?Pericarp structure and phylogeny of the Lamiaceae-Verbenaceae-complex?, Plant Systematics and Evolution, vol. 198, pp. 101?141, 1995.

S. J.  WAGSTAFF, Hickerson, L., Spangler, R., Reeves, P. A., and OLMSTEAD, R. G., ?Phylogeny in Labiatae sl, inferred from cpDNA sequences?, Plant Systematics and Evolution, vol. 209, pp. 265?274, 1998.