The mathematician and historian B. L. van der Waerden suggests that Book VII derives from a textbook on number theory written by mathematicians in the school of Pythagoras.
Əmasaɗinan əd awtifust B. L. Ɣan der Waerden aɣelan alkitab ƔII adigmaɗan manuel fal ən tabarat tan maɗinan iktaban fal əmasaɗinan wən taɣare ən Pythagore