Musannaf Ibn Abi Shayba 1:990

990. Abd al-A’la narrated to us, from Burd, from Makhul, regarding a man who has a wet dream while his wife is at his side, and some of his fluid touches her: That there is no *ghusl* (full ritual bath) upon her, and she should wash [the area] where it touched her, unless it touches her private part, then she must perform *ghusl*.