Hasherucf is right that unless you buy a version controlled copy from the manufacturer or one of the providers (eg Avantext) then its not an approved document. But the reality is that the maintenance schedules & procedures haven't really changed much in the last 30 years. For armchair reference they are fine. And from my experience, its a pretty rose coloured glasses view of the world to think that LAME's have current version controlled approved copies. In my experience about 1 in 10 do.