1. R. Pleiner, Pomatky Archeol. 60 (1969) p. 458.
2. R.F. Tylecote, N.J. Austin, and A.E. Wraith, J. Iron Steel Inst. 209 (1971) p. 342.
3. E.J. Wynne and R.F. Tylecote, J. Iron Steel Inst. 190 (1958) p. 140.
4. M.E. Dingle, J. Stanko, and D.D. Howat, J. So. African Inst. Mining Metallurgy, 74 (1974) p. 268.
5. L.M. Pole, Bull. Hist. Metallurgy Group, 8 (1975) p. 21.