Musannaf Ibn Abi Shaybah 19254 — Those who said divorce goes

When I came to Madinah, I wrote to Abu Qilabah, and he wrote back to me that someone whose narration I trust narrated to him that Zayd bin Thabit and Qabisah bin Dhu'ayb said: If her husband is free and she is a slave-girl, his divorce is the divorce of a free man and her waiting period is the waiting period of a slave-girl; and if her husband is a slave and she is free, his divorce is the divorce of a slave and her waiting period is the waiting period of a free woman.