Semaw, S.; Renne, P.; Harris, J. W. K.; Feibel, C. S.; Bernor, R. L.; Fesseha, N.; Mowbray, K. 2.5-million-year-old stone tools from Gona, Ethiopia. Nature. 1997, 385 (6614): 333–6. Bibcode:1997Natur.385..333S. PMID 9002516. doi:10.1038/385333a0.
Semaw, S.; Renne, P.; Harris, J. W. K.; Feibel, C. S.; Bernor, R. L.; Fesseha, N.; Mowbray, K. 2.5-million-year-old stone tools from Gona, Ethiopia. Nature. 1997, 385 (6614): 333–6. Bibcode:1997Natur.385..333S. PMID 9002516. doi:10.1038/385333a0.
Semaw, S.; Renne, P.; Harris, J. W. K.; Feibel, C. S.; Bernor, R. L.; Fesseha, N.; Mowbray, K. 2.5-million-year-old stone tools from Gona, Ethiopia. Nature. 1997, 385 (6614): 333–6. Bibcode:1997Natur.385..333S. PMID 9002516. doi:10.1038/385333a0.