Źródła
- Half-Life (PC), Valve Software, 1998.
- Half-Life: Opposing Force (PC), Gearbox Software, 1999.
- Half-Life: Blue Shift (PC), Gearbox Software, 2001.
- Half-Life: Decay (PS2), Gearbox Software, 2001.
- Half-Life 2 (PC), Valve Software, 2004.
- Half-Life: Blue Shift (instrukcja do gry), Gearbox Software, 2001.