Semifinals???

Where do I buy the tickets for the semi-finals in 2016 "Semifinals: October 21-22 at Madison Square Garden in New York, NY".

I've been trying to find a website that sells the tickets, but I am not able to.

Here is proof that this is legit: http://www.lolesports.com/en_US/articles/2016-world-championship-hits-north-america