Greg Coomer - Combine OverWiki, the original Half-Life wiki and Portal wiki

Valve Corporation - Closing Logos

Jon St. John - Combine OverWiki, the original Half-Life wiki and Portal wiki

Steam közösség :: Útmutató :: The Character Information Guide

Rhys Darby - Combine OverWiki, the original Half-Life wiki and Portal wiki

Adam Baldwin - Combine OverWiki, the original Half-Life wiki and Portal wiki

Steam Community :: Guide :: The Character Information Guide

Gordon Freeman, Half-Life Wiki

Greg Coomer - Combine OverWiki, the original Half-Life wiki and Portal wiki

Rich Sommer - Combine OverWiki, the original Half-Life wiki and Portal wiki

Ozioma Akagha - Combine OverWiki, the original Half-Life wiki and Portal wiki

Developer Commentary (Left 4 Dead), Left 4 Dead Wiki