Musannaf Ibn Abi Shayba 21:482

Ja'far ibn 'Awn narrated to us, from Abu al-'Umays, from 'Awn, who said: Asma' bint Abi Bakr said: Whoever recites the Opening of the Book (al-Fatiha), "Say, He is Allah, [who is] One" (al-Ikhlas), "Say, I seek refuge in the Lord of daybreak" (al-Falaq), and "Say, I seek refuge in the Lord of mankind" (an-Nas) after the Friday prayer, will be protected between it and the [next] Friday.