1. K.L. Luthra, H.S. Ray, and Dharmendra Kumar: J. Int. Eng. (India), 1973, vol. 53, pp. 58–65.
2. A. Voisky and E. Sergievskaya: Theory of Metallurgical Process (Pyrometallurgical Processes), Mir Publishers, Moscow, 1971, pp. 343–55.
3. A.S. Russel: J. Met., 1981, vol. 33, pp. 132–37.
4. T.K. Mukherjee and C.K. Gupta: Mineral Process. Tech. Rev. 1983, vol. 11, pp. 111–53.
5. W.E. Dunn, Jr.: Trans. AIME, 1960, vol. 218, pp. 6–12.