There's actually a relatively new book about Kubrick's influences on other filmmakers (believe it or not, the first of its kind). It's called After Kubrick: a Filmmaker's Legacy (ed. Jeremi Szaniaswski). PTA is discussed thoroughly.
This: https://www.amazon.co.uk/Paul-Thomas-Anderson-Adam-Nayman/dp/1419744674
Big coffee table book made by the Little White Lies people, I believe.
I was never bored during the movie. The guy sitting next to me, though, couldn't sit still and it drove me nuts.
I was confused out of my mind, but never bored. If you have 40 minutes, listen to Slate's Spoiler podcast on IV: http://www.stitcher.com/podcast/slates-spoiler-specials-14530/e/inherent-vice-slates-spoiler-special-36415839
They have some very interesting insights on the movie. I really want to see it again.
Lucky me I got it on Blu-ray years ago from a local store here in México.
Check it out on Amazon, here: