Reisizadeh, H., Ruan, J., Liu, S., & Hong, M. (2026). Do LLMs Really Forget? Hidden-State Leakage in Model Unlearning and How to Fix it. https://omanscience.com/en/articles/do-llms-really-forget-hidden-state-leakage-in-model-unlearning-and-how-to-fix-it