P.  Martonfi, ?Pollen morphology of Thymus sect. Serpyllum (Labiatae : Mentheae) in the Carpathians and Pannonia?, Grana, vol. 36, pp. 261?270, 1997.

M.  Harley, Paton, A., Harley, R., and Cade, P., ?Pollen morphological studies in tribe Ocimeae(Nepetoideae: Labiatae). I: Ocimum L.?, Grana, 1992.