Chung, H. G., et al. “Studies on the Essential Oil of Different Fennel (Foeniculum Vulgare Mill.) Populations During Onthogeny”. International Journal of Horticultural Science, vol. 5, no. 3-4, Sept. 1999, pp. 27-30., https://doi.org/10.31421/IJHS/5/3-4/38.