I had a professor in college who quoted Bonhoeffer a lot. Sadly, I do not remember any of those quotes. A case of remembering facts only long enough in order to regurgitate them on a test.
A few years ago a friend shared a video with me about Bonhoeffer. I’d never heard of him before. A remarkable person.
Here’s a book by one of my former professors (Mark Devine) on Bonhoeffer:
http://www.amazon.com/Bonhoeffer-Speaks-Today-Following-Jesus/dp/0805432612