Abdounur, Oscar João Department Structural Changes in Systems of Knowledge, Max Planck Institute for the History of Science, Max Planck Society;
http://revistas.pucsp.br/index.php/circumhc/article/view/2757 (Any fulltext)
Abdounur, O. J. (2009). A preliminary survey on the emergence of an arithmetical theory of ratios. Circumscribere, 7, 1-8.