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Uh ... the first one is the icon for history, favorites, and bookmarks in Safari, so why would it be the icon for iBooks? The second or third will be the icon as it correlates strongly with the Mavericks iBooks app icon.
 
If we we to leave all skeuomorphism behind, I think it might look something like this...

2d2gheg.jpg
 
I'm pretty sure #1 was the one found buried somewhere in iOS 7, so that looks to be the real one. I much prefer either #2 or #3. I don't like the overly simplified book icon because it's the same icon as bookmarks, and those are two different things. Also, the one from OS X looks better, and it would be better to have the icons be consistent.
 
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