A. Murasmita, Meirina Mulia W, Maria Galuh K, Dita Eka N, and Ervina Rosmarwati, “Differences in Facial Skin Acidity Levels of Nurses in Sebelas Maret University Hospital, Before and After Surgical Mask Use During the COVID-19 Pandemic ”, Bioscmed, vol. 7, no. 12, pp. 3851-3854, Nov. 2023.