Sahih Muslim
The Book of Prayers (Kitab Al-Salat)
Book Number: 004 / Hadith Number: 1767
This hadith has been transmitted by Qatada with the same chain of transmitters. But Shu'ba (one of the narrators) said: At the end of Surah al-Kahf, but Hammam said: At the beginning of Surah al-Kahf.