1. M. E. Adams-J. Sichler, Homomorphisms of bounded lattices with a given sublattice (to appear).
2. L. Babai, Embeddings of categories, Thesis, Eötvös L. University (Budapest, 1973; in Hungarian); unpublished.
3. L. Babai-J. Nešetřil: High chromatic rigid graphs,Proc. 5th Hungarian Kombinat. Coll., (Keszthely, 1976), North Holland.
4. P. Erdős-R. Rado, Intersection theorems for systems of sets I,J. London Math. Soc.,35 (1960), 85–90.
5. E. Fried, Categorical properties of integral domains (to appear).