1. R. D. Heyding,Can. J. Chem., 44(10), p 1233–1236 (1966).
2. R. M. Murray and R. D. Heyding,Can. J. Chem., 53(6), p 878–887 (1975).
3. A. A. Babitsyna, T. A. Emelyanova, M. A. Chernitsyna and V. T. Kalinnikov,Zh. Neorg. Khim., 20(11), p 3093–3096 (1975) in Russian; translated asRuss. J. Inorg. Chem., 20(11), p 1711–1713 (1975).
4. G. P. Bernardini and A. Catani,Miner. Deposita (Berl.),3(4), p 375–380 (1968).
5. G. P. Bernardini, F. Corsini and R. Trosti,Period. Miner., 41(3), p 565–586 (1972) in Italian.