Sunan Ibn Majah, Book 25, Hadith 3110 (In-Book) ⓘ
It was narrated from Ibn ‘Abbas that the Messenger of Allah did not perform any ‘Umrah except in Dhul-Qa’dah.”
حَدَّثَنَا عُثْمَانُ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا يَحْيَى بْنُ زَكَرِيَّا بْنِ أَبِي زَائِدَةَ، عَنِ ابْنِ أَبِي لَيْلَى، عَنْ عَطَاءٍ، عَنِ ابْنِ عَبَّاسٍ، قَالَ لَمْ يَعْتَمِرْ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ إِلاَّ فِي ذِي الْقَعْدَةِ .
also referenced under: Hadith 2996 (Reference) & Volume 4, Book 25, Hadith 2996 (DarusSalam)