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.