1. The Chemistry of Thallium; Elsevier, Amsterdam, 1971, pp. 73-75.
2. The high frequency paramagnetism and electronic configuration of post-transition metal ions in pure salts
3. (a) Some Physical Properties of the Covalent Link in Chemistry, Cornell University Press, Ithaca, NY, 1933, pp. 189 and 210;
4. (c) The Chemical Elements and their Compounds, Clarendon Press: Oxford, UK, 1950, vol. 1, p. 287;