1. Webster. The Merriam-Webster Dictionary, International Edition; 2016.
2. [No title]. http://worrydream.com/refs/Sutherland%20-%20The%20Ultimate%20Display.pdf. Accessed 11 Sept 2019.
3. Cipresso P, Giglioli IAC, Raya MA, Riva G. The past, present, and future of virtual and augmented reality research: a network and cluster analysis of the literature. Front Psychol. 2018;9:2086.
4. Chinnock C. Virtual reality in surgery and medicine. Hosp Technol Ser. 1994;13:1–48.
5. Cyberspace: The New Explorers: Autodesk : Free Download, Borrow, and Streaming : Internet Archive.