edited by C. Moura Branco and L. Guerra Rosa. edited by J. L. Alonso and R. Tarrach. edited by A. Villa and G. Murari. edited by G. F. Bertsch and D. Kurath. edited by G. Grossmann and L. Ledebo. edited by M.P. Ferranti and G.L. Ferrero. edited by D. Skerrow and C.J. Skerrow. edited by I. M. Barbour and A. T. Davies. edited by P. Hodge and D. C. Sherrington. edited by R. Baran and R.P.R. Dawber.