You can find citations in academic articles, books, research papers, and online databases like Google Scholar, JSTOR, PubMed, etc. Citations are also present at the end of news articles or blog posts, referenced as sources. Websites like EasyBib or Citation Machine can help generate citations in various formats. Libraries also have resources for citation and the Purdue Online Writing Lab (OWL) is a great online resource for citation guidelines. Always remember to credit the original source of information to avoid plagiarism.