Space and Time in Contemporary Physics: Moritz Schlick (translation by H. L. Brose). Clarendon Press, Oxford, 1920.
THE SPECIAL THEORY
The Principle of Relativity: E. Cunningham. Camb. Univ. Press.
Relativity and the Electron Theory: E. Cunningham, Monographs on Physics. Longmans, Green & Co.
The Theory of Relativity: L. Silberstein. Macmillan & Co.
The Space-Time Manifold of Relativity: E. B. Wilson and G. N. Lewis, Proc. Amer. Soc. Arts & Science, vol. XLVIII., No. 11, 1912.
THE GENERAL THEORY
Report on the Relativity Theory of Gravitation: A. S. Eddington. Fleetway Press Ltd., Fleet Street, London.
On Einstein's Theory of Gravitation and its Astronomical Consequences: W. de Sitter, M. N. Roy. Astron. Soc., LXXVI. p. 699, 1916; LXXVII. p. 155, 1916; LXXVIII. p. 3, 1917.
On Einstein's Theory of Gravitation: H. A. Lorentz, Proc. Amsterdam Acad., vol. XIX. p. 1341, 1917.