WITNESS

ʿAmal birkār yuʿraf bihi al-awqāt li-al-ṣalāh_Berlin_Staatsbibliothek (Berlin)_Landberg_56

References

Charette, François, and Petra Schmidl. 2004. “Al-Khwārizmī And Practical Astronomy In Ninth-Century Baghdad, The Earliest Extant Corpus Of Texts In Arabic On The Astrolabe And Other Portable Instruments”. Sciamvs 5: 101-98.

P. 105, text 3.