Monadic NP and Graph Minors

On preservation under homomorphisms and unions of conjunctive queries

PODS '04 Proceedings of the twenty-third ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems

On preservation under homomorphisms and unions of conjunctive queries

Journal of the ACM (JACM)

Homomorphism preservation on quasi-wide classes

Journal of Computer and System Sciences

On nowhere dense graphs

European Journal of Combinatorics

Finite model theory on tame classes of structures

MFCS'07 Proceedings of the 32nd international conference on Mathematical Foundations of Computer Science