Luo, Y., J. Ji, X. Sun, L. Cao, Y. Wu, F. Huang, C.-W. Lin, and R. Ji. “Dual-Level Collaborative Transformer for Image Captioning”. Proceedings of the AAAI Conference on Artificial Intelligence, vol. 35, no. 3, May 2021, pp. 2286-93, https://ojs.aaai.org/index.php/AAAI/article/view/16328.