(49) باب تَرْتِيلِ الْقِرَاءَةِ وَاجْتِنَابِ الْهَذِّ وَهُوَ الإِفْرَاطُ فِي السُّرْعَةِ وَإِبَاحَةِ سُورَتَيْنِ فَأَكْثَرَ فِي الرَّكْعَةِ
This hadith has been narrated by A'mash with the same chain of transmitters in which ('Abdullah b. Mas'ud) said:
" I know the manners in which the Messenger of Allah (ﷺ) recited the two surahs in one rak'ah and then twenty surahs in ten rak'ahs."
Reference: Sahih Muslim 822 c
In-book reference: Book 6, Hadith 338
USC-MSA web (English) reference(deprecated numbering scheme): Book 4, Hadith 1793