# ε∇4 R 4 type invariants and their gradient expansion

> Research article (Journal of High Energy Physics, 2015) · cited 33× · AI/ML

**Wikidata**: [openalex:W1755592127](https://www.wikidata.org/wiki/openalex:W1755592127)  
**Source**: https://4ort.xyz/entity/4-r-4-type-invariants-and-their-gradient-expansion