[SQL] system catalog info

[Ron Peterson]

The HTML programming documentation (e.g.
http://www.postgresql.org/devel-corner/docs/programmer/pg-system-catalogs.htm)
indicates that more extensive information about the system catalogs can
be found in the "Reference Manual".  Where can this reference manual be
found?  Or where can more extensive documentation about the system
catalogues be found?

-Ron-