C. Ausielle and M. Protasi.Colloquium on Trees in Algebra Programming(8th : 1983 : L`Aquila, It)：CAAP`83, Colloque sur les arbres en Algebre et en Programmation; 8th Colloquium, March 9-11, 1983 ; proceedings.Springer,1983.
Colloquium on Trees in Algebra Programming(8th : 1983 : L`Aquila, It)：CAAP`83, Colloque sur les arbres en Algebre et en Programmation; 8th Colloquium, March 9-11, 1983 ; proceedings
