Musannaf Ibn Abi Shayba 18:403

Abu Bakr narrated to us, he said: Ad-Dahhak ibn Makhlad narrated to us, from Ibn Jurayj, who said: I asked ‘Ata’ about the fingernail when it does not grow. He said: I have heard something regarding it from Sa‘d, and I do not know what it is that he cares about.