Zotero is a great tool for organizing sources that you find on the open web or in library databases. It is "free, easy to use tool to help you collect, organize, cite and share research. Zotero allows you to easily save bibliographic details, comments, indexing terms, and direct links to webpages, word documents, and even articles that are in library subscription databases. It is compatible with Windows and Mac OS. You will also need a connector (like an add-on or extension) for your browser. All the major browsers are supported.