* [http://www.genesis8bit.fr/amstrad/game-rom/amstrad-game.php?prog_id=1433&title=Doppleganger&creator=Alligata Genesis 8Bit]
* [http://www.video-games-museum.com/en/game/Doppleganger/38/3/11879 Video Games Museum]
* [http://www.amstradabandonware.com/en/game/knightmare/871 Amstrad Abandonware]
== Download ==
* [http://tacgr.emuunlim.com/downloads/filedetail.php?recid=259 The Amstrad CPC Games Resource]