¨ Code of the Quipu: A Study in Media, Mathematics, and Culture, M. Ascher and R. Ascher, University of Michigan Press, Ann Arbor, 1981. This book has been reprinted as Mathematics of the Incas: Code of the Quipu, Dover Publications, New York, 1997.
¨"The quipu as a visible language", M. Ascher and R. Ascher, Visible Language, 9(1975) 329-356. [Spanish translation: "El quipu como languaje visible" in Runakunap Kawsayninkupaq Rurasquankunaqa (La Technologia En El Mundo Andino), H. Lechtmen y A. M. Soldi, eds., Instituto de Investigaciones Anthropologicas del Universidad Nacional Autonama de Mexico, 1980.]
¨"The logical-numerical system of Inca quipus", M. Ascher, Annals of the History of Computing, 5(1983) 268-278. [Spanish translation: "El sistema lógico-numérico de los Incas" in Quipu Y Yupana, C. Mackey et al, eds., Consejo Nacional de Ciencia y Technologiá, Lima, 1990.]
¨"Mathematical Ideas of the Incas", M. Ascher, in Native American Mathematics, M. Closs, ed., University of Texas Press, Austin, 1986, pp. 261-289. [Spanish translation: "Ideas matematicas de los Incas", Pueblos Indigenas Y Educacion, 2(1988) 41-70.]
¨"Reading khipu: labels, structure, and format", M. Ascher, pp.87-102 in Narrative Threads: Accounting and Recounting in Andean Khipu, J. Quilter and G. Urton, University of Texas Press, Austin, 2002.
¨"Inka writing",
R. Ascher,pp.103-115 in Narrative Threads: Accounting and Recounting in Andean
Khipu, J. Quilter and G. Urton, University of Texas Press, Austin, 2002.
Contents of the Databooks and How to Use Them