Evaluation of saliva glutathione, glutathione peroxidase, and malondialdehyde levels in head-neck radiotherapy patients - Derindağ, G; Akgül, H M; Kızıltunç, A; Özkan, Hİ; Kızıltunç Özmen, H; Akgül, N (Turk J Med Sci, 2021)