Evin, E., A. Hrivnák, and J. Tkáčová. “Measurement and Evaluation of Friction Ratios at Deep Drawing”. Advanced Technologies and Materials, vol. 26, no. 2, Dec. 2001, pp. 81-88, https://atm-journal.uns.ac.rs/index.php/atm/article/view/jtp.2001.27.2.8.