Öznur E. Akçin and R. Binzet, “The micromorphological and anatomical properties of <i>Onosma angustissimum</i> Hausskn. & Bornm. and <i>O. cassium</i> Boiss. (Boraginaceae)”, Bangladesh J. Plant Taxon, vol. 17, no. 1, pp. 1–8, Jun. 2010.