Musannaf Ibn Abi Shayba 3:414

Abu Bakr narrated to us, he said: Muhammad ibn Bakr narrated to us, from Ibn Jurayj, who said: I said to ‘Ata’, "Does a woman sit in the second rak‘ah on her left side?" He said, "Yes." I said, "Is it more beloved to you than the right side?" He said, "Yes." He said, "She should gather herself while sitting as much as she is able." I said, "Does she sit like the sitting of a man in the second rak‘ah, or does she bring her left leg out from under her buttocks?" He said, "It does not harm her whichever of those she sits in, as long as she gathers herself."