1. 1) U.S. Geological Survey, Iron and Steel, Minerals Yearbook 2007, Advanced Release, U.S. Department of Interior, Washington DC, (2009), 37.5.
2. 2) F. Grobler and R. C. A. Minnitt: JSAIMM, March/April, (1999), 111.
3. 3) 2008 World Direct Reduction Statistics, Midrex Technology Inc., North Carolina, (2010).
4. 4) Y. Ono: Tetsu-to-Hagané, 79 (1993), N711.
5. 5) Y. Ujisawa, K. Nakano, Y. Matsukura, K. Sunahara, S. Komatsu and T. Yamamoto: ISIJ Int., 45 (2005), 1379.