Usman, Arifuddin, Arimbi Arimbi, and Muriyati Muriyati. 2017. “The Effect of Caffeine on VO2Max Athletes Ability”. International Journal of Sciences: Basic and Applied Research (IJSBAR) 35 (3):259-61. https://www.gssrr.org/index.php/JournalOfBasicAndApplied/article/view/8008.