Analysis of Covid-19 Neutralizing Antibody Levels Post Vaccination using Ichroma? and iFlash Covid-19 Nab, Kahar, Hartono, Prasetyaningrum Sari Prabandari, Fitriah Munawaroh,, and Nugraha Jusak , Pharmacognosy Journal, March 2023, Volume 15, Issue 1, p.171-174, (2023)