Al-Matalib al-'Aliyah 228 — The description of the adhan and its place

Hisham bin Urwah narrates from his father (Urwah bin al-Zubayr) (may Allah have mercy on him) that "he used to call the words of the adhan twice each and say the words of the iqamah once each, that is, an odd number of times."
Imam al-Harith recorded this narration in his Musnad, and its chain is sahih (authentic). This is the authentic practice of Urwah bin al-Zubayr (may Allah have mercy on him), which is evidence for the Sunnah that the words of the adhan are said twice each and the words of the iqamah once each.