V. D. Zheljazkov, Horgan, T., Astatkie, T., and Schlegel, V.,
“Distillation Time Modifies Essential Oil Yield, Composition, and Antioxidant Capacity of Fennel (Foeniculum vulgare Mill)”,
Journal of Oleo Science, vol. 62, no. 9, pp. 665 - 672, 2013.