Where does this quote from Al-Shafi'i originate from?

Question

Where does this quote from Al-Shafi'i originate from? And could I please get a source for the Arabic?

Al-Shafii (d. 820) said: “He may marry off his female slave without her permission whether she is a virgin or non-virgin.”

Quoted by Kecia Ali in Marriage and Slavery, pg. 40

Answer 1

The source of the quote seems quite clear in the edition that is available online. If you see page 40 of the book, next to this quote the author gives a number (46) and the corresponding note for this number gives the citation as:

Al-Umm, K. al-Nikah, "Nikah al-‘adad wa nikah al-'abid," 5:68

I would assume that it refers to the following text:

وله أن يزوج أمته بغير إذنها بكرا كانت أو ثيبا

^{— كتاب الأم - نكاح العدد ونكاح العبيد}