1. Langages algébriques sur le magma libre et sémantique des schémas de programme;Nivat,1972
2. On the interpretation of recursive program schemes;Nivat,1975
3. Non deterministic recursive program schemes;Arnold,1977
4. The algebraic semantics of recursive program schemes;Courcelle,1978
5. Higher type program schemes and their tree languages;Damm,1977