The blog author is the author of Learn You Some Erlang btw (just for others reading this, since it wasn't clear from your comment)
His other writings are good too. I recommend Erlang in Anger.
I've also written http://propertesting.com/, which I'm currently working to turn into a full book with Pragmatic Programmers (with Elixir translations included as well, so that everyone on the BEAM can benefit :) )