1. 1) S. Ohtani, S. Katayama, T. Akasawa, D. Bhattacharya and H. Yaguchi : J. Appl. Metalwork., 4(1986), 245.
2. 3) C. E. Sims : Trans. AIME, 215 (1959), 367.
3. 5) J.Thomas, W.Peppler, S.Geiman and P.Freeman : Mech. Work. Steel Process., 29 (1992), 321.
4. 8) V.Brabie, M.Kawakami and S.Eketorp : Scand. J.Metall., 4 (1975), 273.
5. 9) Non-metallic Inclusions in steel of partIII, ed. by R.Kiessling, The Metals Society, London, (1978), 74.