1. (a) B. Post, in: K.S. Korres (Ed.), Rare Earth Research II, Gordon and Breach, New York, 1964, pp. 107–116.
2. (b) R. Thompson, in: R.J. Brotherton, H. Steinberg (Eds.), Progress in Boron Chemistry, Pergamon, Oxford, 1970, pp. 173–230.
3. (c) T. Lundström, in: R.B. King (Ed.), Encyclopedia of Inorganic Chemistry, Vol. 1, Wiley, New York, 1994, pp. 328–338.
4. (a) C.E. Housecroft, T.P. Fehlner, in: F.G.A. Stone, R. West (Eds.), Advances in Organometallic Chemistry, Vol. 21, 1981, Acadamic Press, New York, pp. 57–112.
5. (b) C.E. Housecroft, Boranes and Metalloboranes, Wiley, New York, 1990.