Below, I suggest a list of books and papers about the Arm architecture.
In this shortlist, I listed the books I'm reading or want to read. How I missed an orientation as well as order suggestions to read them, I thought it would be worth publish it here and as the suggestions and comments are emerging, It is organized as getting a general reading orientation.
Would also suggest adding this one - a little out of date now, but many of the concepts still valid:
ARM System Developer's Guide: Designing and Optimizing System Software