Muwatta Imam Malik (Riwayat Yahya)

Imam Malik, may Allah have mercy on him, said that if a person performs Umrah in Shawwal or Dhu al-Qi'dah or Dhu al-Hijjah, then returns to his country, and then performs Hajj in the same year, then the sacrificial animal (hady) is not obligatory upon him, because he is not a mutamatti'. Rather, the hady is obligatory upon the one who performs Umrah during the months of Hajj and stays in Makkah until Hajj, then performs Hajj.