Paper  bibtex   

@misc{PGSQL2008,
  key       = {PostgreSQL},
  title     = {{PostgreSQL 8.3 -- computer software}},
  year      = 2008,
  month     = 2,
  url={http://www.postgresql.org/},
  urldate={2009-01-22},
  address   = {PostgreSQL Global Development Group},
}