Full reference OpenMind biblio ref
Kennedy, Edward, and Yusuf ʿId. 1974. “A Letter Of Al-Bīrūni: Ḥabash Al-Ḥāsib`s Analema For The Qibla”. Historia Mathematica 1: 3-11.
{ Edward Kennedy, Yusuf ʿId, 1974 #10973 }