Musannaf Ibn Abi Shayba 3:2471

Hushaym narrated to us, he said: Sayyar and al-Mughirah informed us, from al-Sha'bi; and Yunus and Mansur informed us, from al-Hasan; and Hajjaj, from 'Ata'; and Shu'bah, from al-Hakam; they said: He gives the salutation and enters with the Imam in his prayer.