1. Contiguous r.e. degrees. In: Proceedings of Logic Colloquium '83 (Aachen), Springer Lecture Notes in Mathematics 1104 (1984), pp. 1–37.
2. On the structure of the recursively enumerable degrees. Ph. D. Thesis, University of Munich, 1980.
3. Lattice embeddings into the recursively enumerable degrees
4. Degrees of unsolvability complementary between recursively enumerable degrees, Part 1