كتاب الحج
15  
The Book of Pilgrimage
(17)
Chapter: Clarifying the types of Ihram; and that it is permissible to perfom Hajj that is Ifrad, Tamattu and Qiran. It is permissible to join Hajj to Umrah. And when the pilgrim who is performing Qiran should exit Ihram
(17)
باب بَيَانِ وُجُوهِ الإِحْرَامِ وَأَنَّهُ يَجُوزُ إِفْرَادُ الْحَجِّ وَالتَّمَتُّعِ وَالْقِرَانِ وَجَوَازِ إِدْخَالِ الْحَجِّ عَلَى الْعُمْرَةِ وَمَتَى يَحِلُّ الْقَارِنُ مِنْ نُسُكِهِ
Sahih Muslim 1211 n

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 Hajj).
حَدَّثَنِي يَحْيَى بْنُ أَيُّوبَ، حَدَّثَنَا عَبَّادُ بْنُ عَبَّادٍ الْمُهَلَّبِيُّ، حَدَّثَنَا عُبَيْدُ اللَّهِ بْنُ عُمَرَ، عَنِ الْقَاسِمِ بْنِ مُحَمَّدٍ، عَنْ أُمِّ الْمُؤْمِنِينَ، عَائِشَةَ - رضى الله عنها - قَالَتْ مِنَّا مَنْ أَهَلَّ بِالْحَجِّ مُفْرِدًا وَمِنَّا مَنْ قَرَنَ وَمِنَّا مَنْ تَمَتَّعَ ‏.‏
Reference : Sahih Muslim 1211n
In-book reference : Book 15, Hadith 132
USC-MSA web (English) reference : Book 7, Hadith 2777
  (deprecated numbering scheme)