How do you include cited work in fictional writing?

I'm a beginner and in the process of writing a fictional scfi book. My book requires lots of facts from other sources. i was wondering legally how do I do my citing for my sources in the story. Do I just say where I got the info from using MLA at the end of the book with a works cited page? I know this question is kind of stupid but I don't want to plagiarize. and how much do I have to reword when using the facts?