1. Jones Humphries, Herling and Dobriner, J. Amer. Chem. Soc., 1951, 73, 3215.
2. Thompson and Torkington, J. Chem. Soc., 1945, 640.
3. Hart well, Richards and Thompson, ibid., 1948, 1436.
4. Hampton and Newell, Analyt. Chem., 1949, 21, 914.
5. Anderson and Seyfried, ibid., 1948, 20, 998.