Adopting Open Textbooks: Open Educational Resources

For content available to you via a Creative Commons, Attribution, Share-Alike license, (CC BY SA)
you may add a Creative Commons license of your own, asserting copyright over the content, but you are constrained from adding any but an additional CC BY SA license.

There are six Creative Commons License types. The distinctions indicate whether or not material is to be directly copied or whether it will be changed and adapted, and whether or not a commercial use is intended. All licenses require that the original creator be attributed.

CC BY: means attribute the author. Allows reusers to distribute, remix, adapt, and build upon the material in any medium or format, so long as attribution is given to the creator. The license allows for commercial use.

CC BY-SA: attribute the author and allow content to be freely shared (You can not place a more restrictive license on what you make use of). Allows reusers to distribute, remix, adapt, and build upon the material in any medium or format, so long as attribution is given to the creator. Allows for commercial use. If you remix, adapt, or build upon the material, you must license the modified material under identical terms.

CC BY-NC: attribute the author, only non-commercial uses allowed. Allows reusers to distribute, remix, adapt, and build upon the material in any medium or format for noncommercial purposes only, and only so long as attribution is given to the creator. 

CC BY-ND: attribute the author, no derivatives. Allows reusers to copy and distribute the material in any medium or format in unadapted form only, and only so long as attribution is given to the creator. The license allows for commercial use. 

CC BY-NC-ND: attribute the author, no commercial use, no derivatives. Allows reusers to copy and distribute the material in any medium or format in unadapted form only, for noncommercial purposes only, and only so long as attribution is given to the creator. 

CC 0 public domain, no license required. This is a public dedication tool, which allows creators to give up their copyright and put their works into the worldwide public domain. Allows reusers to distribute, remix, adapt, and build upon the material in any medium or format, with no conditions.