Akgul, M Ozcan, A. “Chemical Composition of the Essential Oil of Bitter Fennel (Foeniculum Vulgare Subsp. Piperitum)”. Journal of Spices and Aromatic Crops 10, no. 1 (June 24, 2001): 49–50. Accessed October 5, 2025. https://www.updatepublishing.com/journal/index.php/josac/article/view/4643.