1. Abd El-Twab, M. H. and Kondo, K. 2003. Physical mapping of 45S rDNA loci by fluorescent in situ hybridization and Evolution among polyploid Dendranthema species. Chrom. Sci. 7: 71-76.
2. Androshchuk, A. F. and Kostinenko, I. L. D. 1981. Chromosome numbers of the genus Achillea L. Certain species cultivated in botanical gardens. Ukrajins'kyj Botaničnyj journal 38: 53-57.
3. Nature of tetraploidy in matricaria inodora l..
4. Badr, A., E. A. Kamel and N. Garcia-Jucas 1997. Chromosomal studies in the Egyptian Flora VI. Karyotype features of some species in subfamily Asteroideae (Asteraceae). Compositae Newsletter 30: 15-28
5. Baker, R. J. and Bickham, J.W. 1986. Speciation by monobrachial centric fusions. Proc. Natl Acad. Sci. S.A. 83: 8245-8248.