Chemische Berichte, , vol. 61, p. 1124 Journal of the Chemical Society, , p. 2907 Chemische Berichte, , vol. 61, p. 1949 Nature (London, United Kingdom), vol. 121, p. 940 Nature (London, United Kingdom), vol. 122, p. 313 Journal of the Chemical Society, , p. 1316 Nature (London, United Kingdom), vol. 122, p. 130 Nature (London, United Kingdom), vol. 122, p. 313 Chem. Zentralbl., , vol. 99, # II p. 1879 Nature (London, United Kingdom), vol. 122, p. 130 Chem. Zentralbl., , vol. 99, # II p. 2238