Besler, G. “Gottlob Frege on Numbers. An Attempt to Determine the Role of the History of Mathematics in the Work of Philosophers”. Philosophical Problems in Science (Zagadnienia Filozoficzne W Nauce), no. 53, Dec. 2013, pp. 133-64, https://www.zfn.edu.pl/index.php/zfn/article/view/60.