[ULPIANUS libro uicensimo nono ad edictum. ] §15.3.13.prSi in rem alterius ex dominis uersum sit, utrum is solus in cuius rem uersum est an et socius possit conueniri, quaeritur.
[ULPIAN, On the Edict, book 29] If it has been turned to the account of one of two masters, the question is whether only he to whose account it was turned can be sued, or whether his partner can be sued as well.
et Iulianus scribit eum solum conueniri in cuius rem uersum est, sicuti cum solus iussit: quam sententiam puto ueram.
And Julian writes that only he to whose account it was turned can be sued, just as when he alone gave the order; which opinion I think is correct.