Marcus Tullius Cicero (1879). “Cicero's Three Books Of Offices: Or Moral Duties; Also His Cato Major, an Essay on Old Age; Laelius, an Essay on Friendship; Paradoxes; Scipio's Dream; and Letter to Quintus on the Duties of a Magistrate”
Marcus Tullius Cicero (1872). “The Academic Questions: Treatise De Finibus and Tusculan Disputations of M. R. Cicero, with a Sketch of the Greek Philosophers Mentioned by Cicero”, p.252