Institutio Oratoria
Quintilian
Quintilian. Institutio Oratoria, Volume 1-4. Butler, Harold Edgeworth, translator. Cambridge, Mass; London: Harvard University Press, William Heinemann Ltd., 1920-1922.
Fortune sometimes is so kind that a witness gives an answer involving some inconsistency, while at times (and this is a more frequent occurrence) one witness contradicts another. But acute examination methodically conducted will generally reach the same result which is so often reached by chance.