Xu J, Du X, Ao Y, Zhao P, Li Y, Zhong L, et al. Thinker: Training LLMs in Hierarchical Thinking for Deep Search via Multi-Turn Interaction. AAAI [Internet]. 2026 Mar. 14 [cited 2026 May 15];40(40):34142-50. Available from: https://ojs.aaai.org/index.php/AAAI/article/view/40709