H. G. Chung, É. Németh, and É. Héthelyi, “Studies on the essential oil of different fennel (Foeniculum vulgare Mill.) populations during onthogeny”, Int. j. hortic. sci., vol. 5, no. 3-4, pp. 27–30., Sep. 1999, doi: 10.31421/IJHS/5/3-4/38.