Vilotić, D., Plančak, M., & Popović, M. (2000). Theoretical solution of contact stresses in upsetting of cylinder by spherical concave dies. Advanced Technologies and Materials, 25(1-2), 71–80. Retrieved from https://atm-journal.uns.ac.rs/index.php/atm/article/view/jtp.2000.26.1.8