Musannaf Ibn Abi Shayba 3:1194

Ibn ‘Ulayyah narrated to us, he said: Hisham al-Dastawa’i narrated to us, from Yahya ibn Abi Kathir, from ‘Abdullah ibn Abi Qatadah, from his father, who said: The Prophet, peace and blessings of Allah be upon him, used to recite for us in the first two rak'ahs of Dhuhr, lengthening the first and shortening the second. And he used to do that in the morning prayer, lengthening the first and shortening the second. And he used to recite for us in the two rak'ahs of ‘Asr.