1. Pliny the Elder.Naturalis Historia, 34, 138–139. InGreek and Roman Technology: A Sourcebook; Humphrey, J.W., Oleson, J.P.; Sherwood, A.N. Trans. Routledge: London/New York, 1998; 593–594.
2. Pliny the Elder.Naturalis Historia, 34, 143–146. In Rackam, H. Trans. Loeb Classical Library 934, Harvard University Press: Cambridge, MA, 1999; 138–139.
3. Pliny the Elder.Naturalis Historia,34, 143–146. In Rackam, H. Trans. Loeb Classical Library 934; Harvard University Press: Cambridge, MA, 1999; 134–136.
4. A Germanic ultrahigh carbon steel punch of the Late Roman-Iron Age