My first step in these situtations is to pull up the book on Amazon, and then check out the "Customers who bought this item also bought" section.

I see a lot of theoretical work in these areas in the Journal of the British Interplanetary Society.

There's a book (out of print) by John W. Macvey called How We Will Reach the Stars. When I read it back in high school it was called Journey to Alpha Centauri. It was science fact about star travel interspersed with chapters of a fictional generation-ship trip to that star. The checkout card in the library book had only my name, over and over again.