1. Ferroxdure, A Class of Permanent Magnet Materials;Went;Philips Tech. Rev,1952
2. Ferroxdure I1 and 111, Aksotropic Permanent-Magnet Materials;Stuiits;ibid,1954
3. 3 R. K. Tenzer , Indiana General Corporation; private communication.
4. Sintering of Ceramic Permanent Magnet Material;Stuijts;Trans. Brit. Ceram. Soc,1956