Sahih Muslim
The Book of Pilgrimage (Kitab Al-Hajj)
Book Number: 007 / Hadith Number: 2777
A'isha (Allah be pleased with her) said: Some among us put on Ihram for Hajj alone (Hajj Mufrad) ; some of us for Hajj and Umra together (Qiran), and some of us for Tamattal (first for Umra and after completing it for Haii).