Øyvind Grøn and Arne Næss—Einstein’s Theory: A Rigorous Introduction for the Mathematically Untrained, Springer, New York, Dordrecht, Heidelberg, London (2011)-ISBN 978-1-4614-0705-8 and David J. Griffiths—Revolutions in Twentieth-Century Physics Cambridge University Press, Cambridge, New York, Melbourne, Madrid, Cape Town, Singapore, São Paulo, Delhi, Mexico City (2013)-ISBN 978-1-107-60217-5