Transformer Neural Networks Explained & Visualized: https://www.youtube.com/playlist?list=PLRgS_r6tnkkhI-q1auABKLfLWG0suOWln
The Illustrated Transformer: http://jalammar.github.io/illustrated-transformer/
T5: a detailed explanation: https://medium.com/analytics-vidhya/t5-a-detailed-explanation-a0ac9bc53e51