Liu, M. H., & Guo, Y. C. (2026). Incremental vs. Stock: Evaluating the Impact of VAT Credit Refunds on Corporate Productivity with Evidence from Difference-in-Differences and Machine Learning Heterogeneity Analysis. Advanced Electromagnetics, 15(3), 4230–4248. https://doi.org/10.7716/aem.v15i3.3486