It must be clear when you've used outside sources in your papers and other work so your reader can:
In order to give proper credit, you must describe the sources in a detailed list (bibliography) at the end of the paper and in brief references to bibliography entries inside the text of the paper whenever information from outside sources is used.
The Modern Language Association (MLA) and American Psychological Association (APA) have both created standard formats for formatting research papers and citing sources.
If you don't cite sources appropriately, you are committing plagiarism and can face serious academic repercussions.
These pages will help you understand the importance of citation and teach you how to cite your sources correctly.