[pdftex] pdf(La)TeX logo copyright

[Magnus Lie Hetland]

Is there a copyright/trademark associated with the (pdf)(La)TeX
logo(s)? Would using these logos in the body text of a (commercial)
book be considered fair use or something? Does anyone have any
authoritative sources on this?

(Sorry if this is off topic...)

-- 
Magnus Lie Hetland                    Fall seven times, stand up eight
http://hetland.org                                  [Japanese proverb]