Cardoso, Danilo, and Ivã Gurgel. “The Complementarity of the Narrative and Mathematical Thoughts in the Development of General Theory of Relativity”. Caderno Brasileiro De Ensino De Física, vol. 34, no. 3, Dec. 2017, pp. 745-73, doi:10.5007/2175-7941.2017v34n3p745.