I would like to use problems from the NPL. According to this page:

http://webwork.maa.org/wiki/WeBWorK:Copyright

all contributions to WeBWorK are considered to be released under the GNU Free Documentation License 1.2.

Does this mean that the problems I find in the WeBWorK NPL are released under the GNU Free Documentation License 1.2?

If not, then what copyright are problems in the NPL under?