In 2015 Chris Green published the last update to his groundbreaking book Online Arbitrage:

While the book is still available via the above link, there are no planned updates. Some information may be outdated as are the offers in the book.

For more information related to Online Arbitrage we recommend joining the Facebook group FBA Today (Amazon Selling) community. 
The group is run by Nate McCallister and is very active. He has a number of articles and recommendations for Online Arbitrage.

Happy sourcing!