References - Magazine articles 

Jelliss, G. (2009). Variant Chess Magazine. [online] www.mayhematics.com. Available at: https://www.mayhematics.com/v/v.htm#:~:text=Variant%20Chess%20magazine.

Stein, P. and Ulam, S. (1957). Experiments in Chess on Electronic Machines. Chess Review, [online] Jan., pp.13–17. Available at: https://uscf1-nyc1.aodhosting.com/CL-AND-CR-ALL/CR-ALL/CR1957/CR1957_01.pdf.