1. Unity Technologies Looks at 1.7 Billion Devices Globally for its Q1 2016 Global “Games by the Numbers” Report.
https://unity3d.com/company/public-relations/news/unitytechnologies-looks-17-billion-devices-globally-its-q1-2016
2. Celebrating an Unreal 2017.
https://www.unrealengine.com/en-US/blog/celebrating-anunreal-2017
3. Unity SIM.
http://www.unity3d.com/industries/sim
. Accessed 7 Mar 2018
4. Unreal Engine 4.
www.unrealengine.com
. Accessed 9 Mar 2018
5. CryENGINE.
http://www.crytek.com/cryengine
. Accessed 3 Mar 2018