Tufnell, Nicholas (November 25, 2011). "Interview: Gabe Newell". The Cambridge Student Online. Archived from the original on November 26, 2011. Retrieved November 26, 2011.
Tufnell, Nicholas (November 25, 2011). "Interview: Gabe Newell". The Cambridge Student Online. Archived from the original on November 26, 2011. Retrieved November 26, 2011.