U-Net: Convolutional Networks for Biomedical Image Segmentation, Olaf Ronneberger, Philipp Fischer, Thomas Brox, 2015Medical Image Computing and Computer-Assisted Intervention – MICCAI 2015DOI: 10.48550/arXiv.1505.04597 - Introduces the original U-Net architecture, detailing its encoder-decoder structure, skip connections, and effectiveness for image segmentation tasks.