Yantono Widarto, Winata, et al. “The Effects of Creatine Snd Protein Supplements on Cystatin C and Serum Creatinine Levels Among Male Weight Training Enthusiasts Aged 20-35 Years in Surabaya Gymnasiums”. International Journal of Health and Pharmaceutical (IJHP), vol. 6, no. 1, Feb. 2026, pp. 367-72, doi:10.51601/ijhp.v6i1.568.