Alfred Tarski. ¿ Qué es la geometria elemental ?Boletin de la Sociedad Matemática Mexicana, ser. 2, vol. 3 no. 2 (for 1958, published 1959), pp. 41–51. - Alfred Tarski. What is elementary geometry?The axiomatic method with special reference to geometry and physics, Proceedings of an International Symposium held at the University of California, Berkeley, December 26, 1957—January 4, 1958. Studies in logic and the foundations of mathematics, North-Holland Publishing Company, Amsterdam1959, pp. 16–29.