eLangdell® content that is not in the public domain is covered by a Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) license.
More to the point:
Feel free to remix and re-share our books.
Seriously.
Redistribute them through other free channels, re-purpose them, edit them.
And while we'd absolutely love to hear what you're doing with our content, you don't need to ask permission. Just give us credit.