Amazon Reviews Exposed: The Truth about Amazon Reviews by Timo Hofstee
Found this book informative because I've heard of others losing all their book reviews that they had posted.
Makes sense some of the rules, but not sure why on some others. Like especially the parts about how to contact others who will read and post reviews on your books.
And why swapping with another author is not the way to go and if you get caught paying others to write a review. Publishers give me ARC copies and I don't know the authors, I just really like to read.
Math is interesting in how the figure out the logistics of it all.