Машинска струка
https://www.youtube.com/watch?v=3odX9yM5hMU
http://ssssvetisavabujanovac.nasaskola.rs/files/Машинци/%D0%9C%D0%B0%D1%88%D0%B8%D0%BD%D1%81%D0%BA%D0%B8%20%D1%82%D0%B5%D1%85%D0%BD%D0%B8%D1%87%D0%B0%D1%80%20%D0%BC%D0%BE%D1%82%D0%BE%D1%80%D0%BD%D0%B8%D1%85%20%D0%B2%D0%BE%D0%B7%D0%B8%D0%BB%D0%B0.pdf