Cretaceous resources, events and rhythms : background and plans for research : [proceedings of the NATO Advanced Research Workshop on Cretaceous Resources and Rhythms. Background and Plans for Research, Digne, France, September 16-22, 1988] - Ginsburg, Robert N.; Beaudoin, Bernard (NATO ASI series : Advanced Science Institutes series. Ser. C. Mathematical and physical sciences ;, 1990)