Gabe Newell - Combine OverWiki, the original Half-Life wiki and Portal wiki

Half-Life (series) - Wikipedia

A New Kind of Protagonist - Half-Life: A Place in the West

Chell of Portal was originally in Episode 3 and/or Half-Life 3 : r/HalfLife

Gabe Newell, Half-Life Wiki

The Orange Box Achievements - Combine OverWiki, the original Half-Life wiki and Portal wiki

Chell from Portal was supposed to appear/play a big role in a Half-Life game (look the comments for my full message) : r/HalfLife

Jamil Higley - Combine OverWiki, the original Half-Life wiki and Portal wiki

Jonathan Coulton - Combine OverWiki, the original Half-Life wiki and Portal wiki

Ex Valve dev Matt Wood on the HL and Portal cross over, Valve planned big things back in 2006-7 with HL and Portal, Gabe said in 2007 Chell will have a relation

David Mertz - Combine OverWiki, the original Half-Life wiki and Portal wiki

Half-Life Wiki:About, Half-Life Wiki

Team Fortress 2 - Official TF2 Wiki