Agreed. The book has gotta be worth $20: <a href="http:&#x2F;&#x2F;www.springer.com&#x2F;us&#x2F;book&#x2F;9783319155234" rel="nofollow">http:&#x2F;&#x2F;www.springer.com&#x2F;us&#x2F;book&#x2F;9783319155234</a>