Session 1: Propagation and System performance Chairma's report B.A. de la Morena.
Session 2: Trough and total Wlectron Content Chairman's report R. Leitinger.
Session 3: Variability and forecasting Chairman's report S. Radicella.
Session 4: Modelling and testing Chairman's report P.A. Bradley.
Poster session: The probability of occurrence o f1 layer and L condition estimated by formulas and by tables.