Institutio Oratoria
Quintilian
Quintilian. Institutio Oratoria, Volume 1-4. Butler, Harold Edgeworth, editor. Cambridge, Mass; London: Harvard University Press, William Heinemann Ltd., 1920-1922.
denique in proverbium usque Graecorum
v1-3 p.170
celebratum est, indoctos a Musis atque a Gratiis abesse.