Or use apx HD or apx LL

While I am rooting for authors to make sure they get what they deserve, I feel like there is a bit of a parallel to textbooks here. As an engineer if I learn about statics from a text book and then go use that knowledge to he’ll design a bridge that I and my company profit from, the textbook company can’t sue. If my textbook has a detailed example for how to build a new bridge across the Tacoma Narrows, and I use all of the same design parameters for a real Tacoma Narrows bridge, that may have much more of a case.