Sahih Bukhari Volume 6, Book 66, Hadith 4998

حَدَّثَنَا عَبْدَانُ، عَنْ أَبِي حَمْزَةَ، عَنِ الأَعْمَشِ، عَنْ شَقِيقٍ، قَالَ قَالَ عَبْدُ اللَّهِ قَدْ عَلِمْتُ النَّظَائِرَ الَّتِي كَانَ النَّبِيُّ صلى الله عليه وسلم يَقْرَؤُهُنَّ اثْنَيْنِ اثْنَيْنِ فِي كُلِّ رَكْعَةٍ‏.‏ فَقَامَ عَبْدُ اللَّهِ وَدَخَلَ مَعَهُ عَلْقَمَةُ وَخَرَجَ عَلْقَمَةُ فَسَأَلْنَاهُ فَقَالَ عِشْرُونَ سُورَةً مِنْ أَوَّلِ الْمُفَصَّلِ عَلَى تَأْلِيفِ ابْنِ مَسْعُودٍ آخِرُهُنَّ الْحَوَامِيمُ حم الدُّخَانُ وَعَمَّ يَتَسَاءَلُونَ‏

Narrated By Shaqiq : Abdullah said, "I learnt An-Naza'ir which the Prophet used to recite in pairs in each Rak'a." Then Abdullah got up and Alqama accompanied him to his house, and when Alqama came out, we asked him (about those Suras). He said, "They are twenty Suras that start from the beginning of Al-Mufassal, according to the arrangement done be Ibn Mas'ud, and end with the Suras starting with Ha Mim, e.g. Ha Mim (the Smoke). and "About what they question one another?" (78.1)