Information from the following sources was used in the compilation of these webpages. We encourage you to consult these works to broaden your knowledge of Albert Einstein and his accomplishments.
Wikipedia, Theory of General Relativity: en.wikipedia.org/wiki/Theory_of_general_relativity
Letters to Roosevelt: hypertextbook.com/eworld/einstein.shtml
Cassidy, David C. (2004) Einstein and Our World. Second Edition. Humanity Books, New York.
Dear Professor Einstein. (2002) Edited by Alice Calaprice. Pometheus Books, New York.
Einstein, Albert. (1950) Out of My Later Years. Philosophical Library, New York.