A. Abood, Sajida, ساجدة, Firas H. Khathyer, and فراس. 2025. “Measurement of Specific Activity of Dihydrofolate Reductase (DHFR) Enzyme and Determination of Folate Content Extracted from UV-Exposed Stem- Derived Callus of Sunflower (Helianthus Annuus L.)”. Rafidain Journal of Science 23 (6):1-11. https://doi.org/10.33899/rjs.2012.59598.