1. Decidable properties of monadic functional schemas;Ashcroft,1971
2. Recursive procedures;deBakker;Math. Center Tracts No. 24, Amsterdam,1971
3. A calculus for recursive program schemes;deBakker,1972
4. A theory of programs;deBakker,1969
5. Recursive schemes, algebraic trees, deterministic languages;Courcelle,1974