1. I. Oftadel, Z.Phys. Chem., 135,291–300 ( 1928) in German.
2. R. Juza,ZAnorg. Chem.,279,129–140(1934) in German.
3. B.A. Fishman, N.M. Pavlyuchenko, N.V. Blagoveshchenskaya, V. A. Bryukvin, L.I. Blokhina, and A. V. Byalyi,Izv. Akad. Nauk SSSR, Met., (4), 51–54 (1992) in Russian; TR:Russ. Metall., (4), 47–50 (1992).