Sahih Bukhari
Prophetic Commentary on the Quran (Tafseer of the Prophet (PBUH))
Volume: 006 / Book Number: 060 / Hadith Number: 394
Narrated Abu Ishaq:
A man asked Al-Aswad, 'is it 'Fahal min-Muddakir' or'..Mudhdhakir?" Al Aswad replied, 'I have heard Abdullah bin Masud reciting it, 'Fahal-min Muddakir'; I too, heard the Prophet reciting it 'Fahal-min-Muddakir' with 'd'.