1. Caffeine – Its identity, dietary sources, intake and biological effects;Graham;Nutr Rev,1978
2. The acute effects of single cup of coffee on ocular biometric parameters in healthy subjects;Uzun;J Curr Ophthalmol,2019
3. Temporal patterns of caffeine intake in the United States;Martyn;Food Chem Toxicol,2018
4. FDA Daily Caffeine Recommendation. Available from: https://www.fda.gov/consumers/consumer-updates/spilling-beans-how-much-caffeine-too-much. [Last accessed on 2021 Feb 05].
5. Caffeine Fact Sheet. Available from: https://mobiel.voedingscentrum.nl/Assets/Uploads/voedingscentrum/Documents/Professional s/Pers/Factsheets/VC_FSheet%20Caffeine_ENG_def%20LR-2.pdf. [Last accessed on 2021 Jun 20].