

This volume is the first of a set of two which contain the invited lectures given at the international seminar of the same title held at the Centre de Mecanique Ondulatoire Appliquee du Centre National de la Recherche Scientifique in Paris (France) from October 1983 to May 1985...

This volume is the second of a set of two which contain 28 selected from the l. j. O invited lectures given at the internatim;al seminar of the same title held at the Centre de Mecanique Ondulatoire Appliquee du Centre National de la Recherche Scientifique in Paris (France) from...
