Muwatta Malik 759

وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ أَبِيهِ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم لَمْ يَعْتَمِرْ إِلاَّ ثَلاَثًا إِحْدَاهُنَّ فِي شَوَّالٍ وَاثْنَتَيْنِ فِي ذِي الْقَعْدَةِ ‏.‏

Yahya related to me from Malik from Hisham ibn Urwa, from his father, that the Messenger of Allah, may Allah bless him and grant him peace, only did three umras, one of them in Shawwal, and two in Dhu'l-Qada

Reference

Muwatta Malik 759

In-book

Book 20, Hadith 55