Current version of DocBook and relationship between OASIS / Doc

Hi  all,

What is the relationship between OASIS and DocBook? Both from an
organizational and specification perspective.

What is prompting this question:
- http://docs.oasis-open.org/docbook/docbook/v5.1/os/docbook-v5.1-os.html
claims that 5.1 is a OASIS Standard
- http://docbook.org/xml/5.1/ appears to be exist, but lacks
docbook-5.1.zip and does not say "There is a specification for this
release."
- http://docbook.org/xml/5.0/ has the zip file and specification sentence
- http://www.oasis-open.org/docbook/xml/ shows 5.0 but not 5.1
- http://www.oasis-open.org/docbook/xml/5.0/index.xml says "<para>This
version has not been released yet.</para>"
- http://www.oasis-open.org/docbook/xml/5.0/index.xml says has an
ancient rcsdate and references alpha1 even though
http://www.oasis-open.org/docbook/xml/ lists newer versions (betas and
releases)


I'd like to understand both the particulars of the above confusion and
the general relationship between the two bodies (domains?) to help
resolve future similar questions.

-- 
Eitan Adler