Selection of papers presented at 3 conferences held in Grenoble, France, Sept. 9-11, 1968, Milan, Italy, July 1-3, 1969, and Varna, Bulgaria, Sept. 14...
Selection of papers presented at 3 conferences held in Grenoble, France, Sept. 9-11, 1968, Milan, Italy, July 1-3, 1969, and Varna, Bulgaria, Sept. 14-19, 1970.