De proprietate sermonum vel rerum - Isidorus, s., arciv. di Sevilla, c. 570-636; Cicero, Marcus Tullius, 106-43 a.C; Uhlfelder, Myra L (American Academy in Rome, 1954)
"This compilation [in Latin] is known in several recensions and has been attributed to various authors, notably to Cicero and to Isidore."