Here's the list of sources I used to put together the How Fast Is It Video Book. These books, videos, and websites also represent resources you can use to do for the research. The meaning of relativity is Einstein's own book on the subject. It's a worthwhile read even if you don't do the math. Hip Thorns book, The Science of Interstellar, covers the science behind the movie. It's a great resource for understanding black holes. Elementary differential geometry, by Baradon Neal, was the textbook I used at San Diego State University. It is well written and covers the foundations and geometry needed for a deeper understanding of general relativity. Another good college textbook is Concepts of Modern Physics by Arthur Breaser. There are two particularly useful sources for learning about relativity theory. One of them is the Stanford University YouTube series presented by Leonard Suskheim. I used it extensively, but it assumes a deep understanding of the math. Better yet, for those who are not familiar with differential equations, Dr. John D. Norton's website is outstanding. Norton has a deep understanding of the subject matter and discusses it in non-mathmatical terms. I used his examples extensively. The gravitational waves, there is no better source than the LIGO site itself, as well as the associated Caltech and MIT site. They have created resources, usable by everyone from middle school to post doctoral students. It also has an outreach facility for teachers. And don't forget, every how fast is it video segment, as a document with the text, links, music, pictures, and notes, located on how far away is it.com slash documents. The following identifies all of my sources. Thanks for watching.