Found in 2 comments on Hacker News
kqr2 · 2014-03-05 · Original thread
O'Reilly is currently having a 50% off sale on this ebook:

http://shop.oreilly.com/product/0636920024057.do?code=WK5STA...

oostendo · 2012-03-15 · Original thread
I'd also like to plug the SimpleCV book from O'Reilly -- also coming soon.

http://shop.oreilly.com/product/0636920024057.do

Full disclosure, I am one of the authors.

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