Domain-Specific Language References

I've been meaning to read up on DSL implementation approaches, possibly for use in a thesis project. This is my initial list of references to review.

Martin Fowler's online book (work-in-progress)

Software Language Engineering: Creating Domain-Specific Languages Using Metamodels

by Anneke Kleppe, pub 12/8/09 (available in Safari Books Online) Eclipse Modeling Project: A Domain-Specific Language (DSL) Toolkit by Richard C. Gronback, pub 3/6/09 (available in Safari Books Online, looks Java heavy) Domain-Specific Development with Visual Studio DSL Tools by Steve Cook; Gareth Jones; Stuart Kent; Alan Cameron Wills, pub 5/24/07 (Safari books online)