A. Colmerauer, Equations et inequations on finite et infinite trees Proceeding of the International conference on the fifth generation of computer systems Tokyo, pp.85-99, 1984.

B. Courcelle, Equivalences and transformations of regular systems???Applications to recursive program schemes and grammars, Theoretical Computer Science, vol.42, pp.1-122, 1986.
DOI : 10.1016/0304-3975(86)90050-2

B. Courcelle, Fundamental properties of infinite trees, Theoretical Computer Science, vol.25, issue.2, pp.95-169, 1983.
DOI : 10.1016/0304-3975(83)90059-2

G. Huet, Resolution d'equations dans les langages d'ordre 1, These d'Etat, 1976.

M. Maher, Complete axiomatization of the algebra of finite, rational et infinite trees, 1988.

S. Vorobyov, An improved lower bound for the elementary theories of trees, Proceeding of the 13th International Conference on Automated Deduction (CADE'96)
DOI : 10.1007/3-540-61511-3_91