Musannaf Ibn Abi Shayba 17:702

'A'idh ibn Habib narrated to us, from Talha ibn Yahya, who said: I heard 'Urwah ibn al-Zubayr, Yahya, 'Isa (the two sons of Abu Talha), and Ibrahim ibn Muhammad ibn Talha say: "When one of you sneezes, let him say: 'May Allah have mercy on you' (Yarhamuk Allah)." He said: "May Allah guide you and set your affairs right (Yahdikum Allah wa yuslih balakum)."