Please post a screen capture of the process options you used to compute these files, to make sure the references are appropriate.
You have a reference section at the end of the page:
https://neuroimage.usc.edu/brainstorm/Tutorials/Statistics#Additional_documentation
This article probably describes something very similar to the permutation tests in Brainstorm:
Pantazis D, Nichols TE, Baillet S, Leahy RM. A comparison of random field theory and permutation methods for the statistical analysis of MEG data, Neuroimage (2005), 25(2):383-94.