1. For general references see the following monographs and review papers: J.Green, J.Lee:Positronium Chemistry (Academic Press, New York, N.Y. 1964);
2. V.I.Goldanskii: At. Energy Rev.6, 3 (1968);
3. J.O.McGervey: InPositron Annihilation, ed. by A.T.Stewart, L.O.Roellig (Academic Press, New York, N.Y. 1967);
4. H.J.Ache: Angew. Chem. (Int. Ed. Engl.)11, 179 (1972)
5. S.J.Tao, J.H.Green: J. Chem. Soc. A, 408 (1968)