Ask HN: Any recommended readings on freemium mobile games' strategies?

Hello Hacker News, long-time reader first-time poster here!

Following the fact that Game of War’s paying players spent an average of $550 on its in-app purchases in 2015[1] and Candy Crush Saga made more than a quarter of Amazon's lifetime earnings in a year[2], I am trying to understand how the top-grossing freemium mobile games are handling the mechanics of addiction and competition to make people spend their money. I am aware my question sounds a little naive in regards to this broad field, but as I am fascinated by this economy, I have to start somewhere.

Thank you in advance for your suggestions!

  [1]: http://venturebeat.com/2016/04/01/game-of-wars-paying-players-spent-an-average-of-550-on-its-in-app-purchases-in-2015/
  [2]: http://www.theatlantic.com/business/archive/2014/02/candy-crush-addictive-game-incredible-business-horrible-investment/283891/