Balevičius R, Kačianauskas R, Mróz Z, Sielamowicz I. Microscopic and macroscopic analysis of granular material behaviour in 3d flat-bottomed hopper by the discrete element method. Arch. Mech. 2007;59(3):231-257. Accessed January 17, 2026. http://am.ippt.gov.pl/index.php/am/article/view/v59p231