A Creative Commons non-commercial share-alike license has been used:
http://creativecommons.org/licenses/by-nc-sa/3.0/
You are free:
- to Share -- to copy, distribute and transmit the work
- to Remix -- to adapt the work
Under the following conditions:
- Attribution -- You must attribute the work and leave copyrights intact.
- Noncommercial -- You may not use this work for commercial purposes (i.e., sell it) – unless you get the licensor's permission.
- Share Alike -- If you alter, transform, or build upon this work, you may distribute the resulting work only under the same or similar license to this one.
You are thus allowed to use it in a commercial environment, but not to sell it.