Musannaf Ibn Abi Shayba 3:676

Waki’ narrated to us, from Sufyan, from Salamah ibn Kuhayl, from Ibrahim ibn Suwayd, who said: Alqamah used to say the taslim to his right: "As-salamu 'alaykum wa rahmatullah," and to his left: "As-salamu 'alaykum wa rahmatullah." He said: And al-Aswad used to say to his right: "As-salamu 'alaykum wa rahmatullahi wa barakatuh," and to his left: "As-salamu 'alaykum wa rahmatullahi wa barakatuh."