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Muftah, A. ., and A. Dhaw. “Evaluation Of Different Solvents For Determination Of Caffeine In Tea Leaves Using UV- Visible Spectrophotometric Method”. Journal of Humanitarian and Applied Sciences, vol. 6, no. 12, Nov. 2023, pp. 277-81, https://khsj.elmergib.edu.ly/index.php/jhas/article/view/265.