Shaped stone balls were used for bone marrow extraction at Lower Paleolithic Qesem Cave, Israel Assaf, Ella ; Caricola, Isabella ; Gopher, Avi ; Rosell, Jordi ; Blasco, Ruth ; Bar, Oded ; Zilberman, Ezra ; Lemorini, Cristina ; Baena, Javier ; Barkai, Ran ; Cristiani, Emanuela Abstract Publication: PLoS ONE Pub Date: April 2020 DOI: 10.1371/journal.pone.0230972 Bibcode: 2020PLoSO..1530972A