Musannaf Ibn Abi Shayba 3:4829

Hushaym narrated to us, from Mughirah and Ubaydah, who informed him from Ibrahim; and from Hajjaj, from Ata and al-Sha'bi; and from Abd al-Malik, from Ata, regarding the menstruating woman: If she becomes pure before the setting of the sun, she prays the Dhuhr and the Asr. And if she becomes pure before the dawn, she prays the Maghrib and the Isha.