Listing SQL books in the documentation

The documentation set contains several references to commercial books
about databases and/or SQL for "more information". Most of these are
rather old by today's standards (93-97), so I think we should do something
about that. Possibilities:

a) Update the list with our favourites of the day

b) Sell advertisement spots for the documentation ;-)

c) Not list any commerical books in the documentation at all

Personally, I'm leaning towards (c) because I feel the documentation
should not be biased in that way, and it makes it look less like "we're
too lazy to document this, please read a book".

Untouched by any of this would of course be references to relevant
academic works and specific references to any kind of text to support
implementation choices, etc.

Comments?

--
Peter Eisentraut peter_e(at)gmx(dot)net http://funkturm.homeip.net/~peter