Correlations between serum vitamin D levels and oxidative stress markers at hospital admission in COVID-19 patients - Atanasovska, Emilija; Petrushevska, Marija; Zendelovska, Dragica; Spasovska, Katerina; Grozdanovski, Krsto; Pavlovska, Kristina; Labachevski, Nikola (Elsevier BV, 2022)