Information quality :
Highest to lowest :
Living documents. (below)Public text, on the internet, verified author, usually not older than 5 years.Public text, on the internet, verified author, but maybe old, less relevant, or outdated.Public text, on the internet, author identified, but not verified.Public text, on the internet.Public video/audio with transcription, on the internet + varients as above.--- for initial purposes of the project, information below this level is generally not considered.Public video/audio, no transcription, on the internet.Public video/audio, not available on the internet.--- information below this level is not considered or handled.Private information, or available in other ways.
A living document is one that is maintained, updated, and re-released if in printed form, by one or more persons. And with the intent, that it continue on. Such that when the current person(s) are no longer able or willing to maintain the document, others will carry on the task, with the same form and intent.
For the purposes of the project, documents that are publicly maintained and published on-line are used.
An good example of such a document, in paper form, and not related to the project is the radio amateurs bible (at least in the west) - the ARRL Handbook. http://www.arrl.org/arrl-handbook-2015
I had read and studied a few versions from 1970's and 1980's, and I think I even bought and owned one from the 1990's.