1. For recent articles see, C. K. Ingold, Structure and Mechanism in Organic Chemistry, Bell, London, 1969, Ch. xiv; H. C. Brown, D. H. McDaniel, and O. Häfliger, article in The Determination of Organic Structures by Physical Methods (ed. E. A. Braude and F. C. Nachod), Academic Press, New York, 1955; G. W. Wheland, The Theory of Resonance in Organic Chemistry, Wiley, New York, 1955, Ch. vii.
2. G. Schwarzenbach, Z. Phys. Chem.,176A, 133 (1936). He gives pK(CH4) = 34, but employed an incorrect value for pK(NH3).
3. L. V. Coulter, J. R. Sinclair, A. G. Cole, and G. C. Roper, J. Am. Chem. Soc., 81, 2986 (1959).
4. H. D. Mulder and F. C. Schmidt, J. Am. Chem. Soc., 73, 5575 (1951)
5. W. L. Jolly, Chem. Rev., 50, 351 (1951)