“Knot numbers used as labels for identifying subject matter of a khipu” (2013) Revista Latinoamericana de Etnomatemática Perspectivas Socioculturales de la Educación Matemática, 6(1), pp. 4–19. Available at: https://www.revista.etnomatematica.org/index.php/RevLatEm/article/view/52 (Accessed: 1 January 2026).