Sahih Bukhari Volume 5, Book 59, Hadith Number 469.

Narrated By Anas : Allah’s Apostle performed four ‘Umras, all in the month of Dhul-Qa’da, except the one which he performed with his Hajj (i.e. in Dhul-Hijja). He performed one ‘Umra from Al-Hudaibiya in Dhul-Qa’da, another ‘Umra in the following year in Dhul Qa’da a third from Al-Jirana where he distributed the war booty of Hunain, in Dhul Qa’da, and the fourth ‘Umra he performed was with his Hajj.