[elsherbini]

These are also available on Stephen Welch's youtube channel[1]. He uploaded the last one in this series Janaury 2015.

[1]: https://www.youtube.com/playlist?list=PLiaHhY2iBX9hdHaRr6b7X...

[kqr2]

Per guidelines : https://news.ycombinator.com/newsguidelines.html

  Please submit the original source. If a post reports on 
  something found on another site, submit the latter.

The youtube URL you cited would probably be a better source link.

[cbennett]

Yes, it was misleading I thought all these videos were original content of that site; in fact, they are original content produced by Welch Labs: http://www.welchlabs.com/