Shanem, Janet, et al. “Frequency of Voice Changes During Covid-19 Infections: A Retrospective Study: Frequency of Voice Changes During Covid-19 Infections: A Retrospective Study”. Pakistan BioMedical Journal, vol. 5, no. 6, June 2022, pp. 80-84, https://doi.org/10.54393/pbmj.v5i6.525.