
Bk. 1, ch. 4. Translated by Robert B. Burke, in: Edward Grant (1974) Source Book in Medieval Science. Harvard University Press. p. 93
Opus Majus, c. 1267
Dans Les Leçons Élémentaires sur les Mathématiques (1795) Leçon cinquiéme, Tr. McCormack, cited in Moritz, Memorabilia mathematica or, The philomath's quotation-book (1914) Ch. 15 Arithmetic, p. 261. https://archive.org/stream/memorabiliamathe00moriiala#page/260/mode/2up
Bk. 1, ch. 4. Translated by Robert B. Burke, in: Edward Grant (1974) Source Book in Medieval Science. Harvard University Press. p. 93
Opus Majus, c. 1267
Source: Recreations in Mathematics and Natural Philosophy, (1803), p. 2
Source: Mathematical Lectures (1734), p. 44
Nicomachus of Gerasa: Introduction to Arithmetic (1926)
“It is not of the essence of mathematics to be conversant with the ideas of number and quantity.”
Source: 1850s, An Investigation of the Laws of Thought (1854), p. 12; Cited in: Alexander Bain (1870) Logic, p. 191
Interview with Harvard Business Review, https://hbr.org/ideacast/2017/08/when-startups-scrapped-the-business-plan.html.3 August 2017