References are sources of information that support claims or ideas in a piece of writing. They can include books, articles, websites, and other materials that provide evidence or context. Properly citing references helps readers verify the information and gives credit to the original authors. In academic and professional settings, references are crucial for maintaining credibility and avoiding plagiarism. Different citation styles, such as APA, MLA, or Chicago, dictate how references should be formatted. Including a reference list at the end of a document allows readers to easily locate the sources used.