Of the other books which I have used I should like to quote, above all, Ernst Mach's classical Mechanics (which has appeared in English), and then the very lucidly written volume by E. T. Whittaker, A History of the Theories of Aether and Electricity (london, Longmans, Green Co., and the comprehensive account of the Theory of Relativity given by Hermann Weyl in his Space, Time, Matter (english translation published by Messrs. Methuen 81: Co., Ltd., Anyone who wishes to penetrate further into Einstein's doctrines must study the latter work. It is impossible to enumerate the countless books and essays from which I have drawn more or less directly. In conformity with the character of the book I have refrained from giving references.
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