Pottage 1974, See in particular the footnote on p. 313.. Pottage, John (1974), "The mensuration of quadrilaterals and the generation of Pythagorean triads: a mathematical, heuristical and historical study with special reference to Brahmagupta's rules", Archive for History of Exact Sciences, 12 (4): 299–354, doi:10.1007/BF01307176, MR0465678
doi.org
Pottage 1974, See in particular the footnote on p. 313.. Pottage, John (1974), "The mensuration of quadrilaterals and the generation of Pythagorean triads: a mathematical, heuristical and historical study with special reference to Brahmagupta's rules", Archive for History of Exact Sciences, 12 (4): 299–354, doi:10.1007/BF01307176, MR0465678