Stołtny, Bartosz, Grzegorz Peruń, Jarosław Kozuba, Tomasz Wojnar, and Adam Stołtny. 2022. “An Evaluation of the Technical Condition of the ROTAX 912S Engine Based on Spectrographic Oil Analysis”. Safety & Defense 8 (2), 18-26. https://doi.org/10.37105/sd.181.