As a best practice, all openly licensed resources, either Creative Commons licenses or even public domain resources, should have a proper attribution. Check out ASCCC OERI helpful Attribution Guide and other resources.
Creative Commons (CC) is a nonprofit organization that enables the sharing and use of creativity and knowledge through free legal tools. Creative Commons licenses are not an alternative to copyright. They work alongside copyright and enable you to modify your copyright terms to best suit your needs. -- From Creative Commons website
The licenses below and their descriptions come from the About the Licenses page of Creative Commons:
This guide is adapted from the Lansing Community College (LCC) Library Research Guide on Open Educational Resources (OER)by Regina Gong and is licensed under a Creative Commons Attribution 4.0 International License.