Jonatan, Andrew, and Retno Asih Setyoningrum. “Serum Vitamin D Levels in Pediatric Patients and Its Association With COVID-19 Clinical Manifestation: A Meta-Analysis and Systematic Review”. GSC Biological and Pharmaceutical Sciences 17, no. 2 (November 30, 2021): 076–085. Accessed August 25, 2024. https://gsconlinepress.com/journals/index.php/gscbps/article/view/gscbps-2021-0328.