1. Adler, W., Oswald, K., Fischer, R., 1994. Exkursionsflora von Österreich. Ulmer, Stuttgart.
2. Asteraceae: Cladistics and Classification;Bremer,1994
3. Syringaresinol glycosides from a tissue culture of Scorzonera hispanica;Bryanskii;Khim. Prir. Soedin.,1992
4. A sesquiterpene glucoside from cultivated cells;Bryanskii;Khim. Prir. Soedin.,1992
5. Scorzonera;Chater,1976