Zotero

Zotero is free and open source, meaning its source code is open and continually improved by an active user base. Zotero is compatible with Windows, macOS, and Linux. It is compatible with the Chrome, Safari, Firefox, and Opera browsers, and has plugins for Microsoft Word and LibreOffice.

Installing Zotero is easy:

1. Save any unsaved work and completely shut down your word processor (e.g., Microsoft Word), if it is running. 
2. Update your browser. (Go here to download the latest versions of all the most popular browsers: http://outdatedbrowser.com/en. Sorry, Zotero is not fully compatible with Microsoft Edge.)
3. Close and restart your browser.
4. Go to zotero.org
5. Click Download Now.
6. Click to download Zotero 5.0 for your operating system. Follow the prompts to complete the install.
7. Go to zotero.org/download and install the Zotero Connector for your browser.

Below is an example of the Zotero client. Notice that it is divided into three segments--one for collections (far left), one that lists items within a collection (middle), and one that presents an individual item's metadata (far right).