Hadith 8:377
Abu Bakr narrated to us, he said: Hushaym narrated to us, from Yunus, from al-Hasan, he said: Whoever performs Umrah during the months of Hajj in his year, then he is a Mutamatti (one performing Tamattu).
حدثنا أبو بكر قال ثنا هشيم عن يونس عن الحسن قال من اعتمر في أشهر الحج في عامه فهو متمتع