A co-founder of the Wikipedia online encyclopedia written in collaborative fashion by the Internet community announced he is launching a rival service edited by experts. A test version of "Citizendium" to be launched this week in Harmon, California will use experienced editors and subject authorities to tune information submitted by web surfers.

"Wikipedia has accomplished great things, but the world can do even better," said Larry Sanger, the Wikipedia founder who is spearheading the Citizendium "free knowledge project."

"By engaging expert editors, eliminating anonymous contribution, and launching a more mature community under a new charter, a much broader and more influential group of people and institutions will be able to improve upon Wikipedia's extremely useful, but often uneven work."

Wikipedia was created in 2001 as a website where users could freely contribute, edit and refine entries. It relied on the principle that people who knew better would correct factual errors introduced by others.

The website was based on "wiki" technology that lets visitors change text as they please. The name "wiki" came from a Hawaiian word meaning quick.

Wikipedia blossomed into a widely consulted online reference bank with accuracy reported to be on par with the Encyclopedia Britannica.

Sanger parted ways with Wikipedia in 2002 and became a vociferouls critic of its accuracy.

The plan for Citizendium is to guarantee more reliable information.

Content from Internet users will have to pass muster with editors, scholars or others with minimum levels of qualifications based on "real world" markers such as college diplomas, according to Sanger.

Citizendium will start with "mirroring" Wikipedia's content and then set out to improve or replace it, according to Sanger.

Participation in the pilot project launching this week was by invitation only. Invitations could be requested at http://www.citizendium.org/cfa.html.

It was expected to take several months for Citizendium to make a public online debut.