Musannaf Ibn Abi Shayba 9:1390

'Affan narrated to us, he said: Hammad ibn Salamah narrated to us, he said: Dawud narrated to us, from al-Sha'bi and 'Ikrimah regarding this [verse]: "And not display their adornment except to their husbands, or their fathers, or their husbands' fathers," until he finished it. They both said: He did not mention the paternal uncle and the maternal uncle because they might describe [the woman] to their sons. And they both said: She should not remove her head covering in the presence of the paternal uncle and the maternal uncle.