1. 4) F. KÖRBER and G. TRÖMEL: Arch. Eisenhüttenw., 7 (1933/34), p.7
2. 5) G. NAGELSCHMIDT: J. Chem. Soc., (London) (1937), p.865
3. 6) H.H. BRANDIJR and E. OVERKOTT: Arch. Eisenhüttenw., 37 (1966), p.21
4. 7) A.V. RUDNENVA and V.V. KAZANSKIY: Russ. Met (Metally) 1 (1966), p.10
5. 8) A. MUAN and E.F. OSBORN: “Phase Equilibria among Oxides in Steelmaking” AddisonWesley Pub. Co. INC. (1965)