[b] EDWARD GIBBON, _op. cit._
[c] GEORGE FINLAY, _History of the Byzantine and the Greek Empires from
716-1453_.
[d] GEORGIUS PACHYMERES, _Historia Byzantina_.
[e] ERNEST LAVISSE AND ALFRED RAMBAUD, _op. cit._
[f] H. GELZER, _op. cit._
[b] EDWARD GIBBON, _op. cit._
[c] GEORGE FINLAY, _History of the Byzantine and the Greek Empires from
716-1453_.
[d] GEORGIUS PACHYMERES, _Historia Byzantina_.
[e] ERNEST LAVISSE AND ALFRED RAMBAUD, _op. cit._
[f] H. GELZER, _op. cit._