（C）2006 Valve Corporation. All rights reserved.

(C)2008 Valve, the Valve logo, Left 4 Dead, the Left 4 Dead Logo. Counter-strike, Steam, the Steam logo, Source, the Source logo, and Valve Source are trademarks and/or registered trademarks of Valve Corporation in the United States and other countries.

(C) 2008 Valve Corporation. All rights reserved. Valve, the Valve log o, Left 4 Dead, Source, and the Source logo are trademarks or registe red trademarks of Valve Corporation in the United States and / or oth er countries.

(C) 2009 Valve Corporation. All rights reserved. Valve, the Valve logo, Left 4 Dead, the Left 4 Dead logo, Source, the Source logo, Half-Life, Counter-Strike, Portal and Team Fortress are trademarks or registered trademarks of Valve Corporation in the United States and/or other countries.