Who should I ask for permission to use information found, specifically on the page http://www.blender.org/education-help/faq/gpl-for-artists/ in an attached appendix of a printed book? My publisher is wanting to make sure any and all references are legitimately obtained.
You should probably drop ton a note, he either can give you that permission, or knows who else to ask for permission.
You don’t have to ask permission for citation or use of quotations or information found through research as long as the work you referenced is cited in text and all information is placed in the citations/bibliography of your publication recognizing the individual(s), entities, websites, groups, etc. from which the information came. This in effect covers you along the lines of plagiarism and copyright infringement. If you are using direct quotes, make sure there are quotation marks around it, if it is paraphrased, you don’t need the quotation marks, but make sure in both cases the works are cited.
You publisher is covering their butt and yours, just in case someone might read something and say, “Hey, I said/wrote that!” and as long as you give credit where credit is due, you won’t have a lot of legal pain. Your citations reflect that person’s work and gives someone a place to look to confirm legitimacy.