Srebrenkoska, S., A. Kochov, and R. Minovski. “Six Sigma and Design of Experiments for Improving the Production of Composite Pipes”. Advanced Technologies and Materials, vol. 41, no. 2, Dec. 2016, pp. 11-18, https://jged.uns.ac.rs/index.php/atm/article/view/jtp.2016.41-2.2.