Musnad Abu Ya'la al-Mawsili 115:31

Hadaba narrated to us, Hammam narrated to us, Qatada narrated to us that Anas informed him that the Prophet, peace and blessings of Allah be upon him, performed four Umrahs, all of them in Dhu al-Qa'dah, except the one that was with his Hajj. His Umrah from al-Hudaybiyyah, or at the time of al-Hudaybiyyah, was in Dhu al-Qa'dah. His Umrah from the following year was in Dhu al-Qa'dah. His Umrah from al-Ji'ranah, when he distributed the spoils of Hunayn, was in Dhu al-Qa'dah. And his Umrah was with his Hajj.