Matrix infrared spectroscopy of intermediates with low co-ordinated carbon, silicon and germanium atoms, V.A. Korolev and O.M. Nefedov; acid-base behaviour in macrocycles and other concave structures, U. Lining; photodimerization and photopolymerization of diolefin crystals, M. Hasegawa; ionic dissociation of carbon-carbon O bonds in hydrocarbons and the formulation of authentic hydrocarbon salts, K. Okamoto.