The Techcrunch article just references the Engadget article https://www.engadget.com/2017/11/30/spacex-falcon-heavy-laun...
And the Engadget article just references an aviation week article (paywalled) http://aviationweek.com/space/falcon-heavy-debut-slips-2018
There's a lot more (non paywalled) information here: https://spaceflightnow.com/2017/11/28/debut-of-spacexs-falco...