1. Bruneton, J. (1995). Pharmacognosy, Phytochemistry, Medicinal Plants. Lavoisier, Publishing. Secaucus NY. pp. 218–9.
2. Rohlf, F. J. (1993). NTSYS-pc Numerical Taxonomy and Multivariate Analysis System version 1.80 Owner’s Manual.
3. Shannon, C. E. and Weaver, W. (1949). The mathematical theory of communication. University of Illinois Press, Urbana, IL, USA.