Arya Raditya Prawira Putra, Dendi, Yudha Purwanto, and Marisa Paryasto. “Implementation of Blockchain As Covid-19 Test and Vaccine Certificate Storage System”. Journal of Computer Engineering 1, no. 02 (November 7, 2022): 63–71. Accessed April 16, 2026. https://journals.telkomuniversity.ac.id/cepat/article/view/5189.