The student includes five supporting documents in their IA, all of which are contemporary, published between 2023 and 2025. Each document is clearly labeled, making it easy to follow the references, and they are relevant and sufficiently in-depth, providing valuable insights into Duolingo's AI strategies and market growth. The student highlights pertinent parts of each document that relate directly to their IA, effectively supporting their analysis. Additionally, the documents present a range of ideas and views on the topic, and the student assesses the validity and reliability of the sources, acknowledging potential biases.