(a) It is narrated from Sayyiduna Abu Sa'id al-Khudri (may Allah be pleased with him): We used to estimate the recitation of the Prophet (peace and blessings be upon him) in Zuhr and Asr. Once we estimated that in the first two rak'ahs of Zuhr he stood for as long as it takes to recite thirty verses, the length of reciting Surah al-Sajdah; in the last two rak'ahs, half of the first two; in the first two rak'ahs of Asr, the same as the last two rak'ahs of Zuhr; and in the last two rak'ahs of Asr, half of the first two.
(b) Abu Awanah narrated this hadith from Mansur and said that he would recite the equivalent of thirty verses in every rak'ah.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 2490