OKLAHOMA CITY -- The NBA has filed for trademark rights to six nicknames for the league's new Oklahoma City franchise: Barons, Bison, Energy, Marshalls, Thunder and Wind.

An attorney for the league made the filing Monday with the U.S. Patent and Trademark Office.

Marshal is usually spelled with one l. It's not clear why the league used a variant spelling.

The filing is listed on the patent office's Web site.

The NBA and the team have refused to discuss possible new names for the team formerly known as the Seattle SuperSonics ahead of an official announcement, which has not yet been scheduled.