Hirano, S., Wada, Y., Matsuda, K., Otsuki, S., & Sugiura, K. (2026). LLM-Free Image Captioning Evaluation in Reference-Flexible Settings. Proceedings of the AAAI Conference on Artificial Intelligence, 40(6), 4708–4716. https://doi.org/10.1609/aaai.v40i6.42472