Tumonis, Liudas, Rimantas Kačianauskas, Arnoldas Norkus, and Daiva Žilionienė. “Comparison Study of Spherical and Multi-Spherical Particles under Cyclic Uniaxial Compression”. Journal of Civil Engineering and Management 18, no. 4 (September 11, 2012): 537-545. Accessed June 5, 2020. https://journals.vgtu.lt/index.php/JCEM/article/view/4485.