The medieval tradition of a Greek mathematical lemma / Wilbur R. Knorr.
Abstract:
The Arabic of this trigonometric lemma provided the source for Latin and Hebrew translations in the 12th and 13th centuries, respectively. An inspection of the medieval versions of the lemma provides additional evidence of its Greek tradition, but more interesting is 'the resultant cross section one derives of the methods of the medieval translators and commentators'
Zeitschrift für Geschichte der Arabisch-Islamischen Wissenschaften Bd. 3 (1986), p. 230-264