Pisma Inoćentija ІІІ.Arhivirano 2010-10-11 na Wayback Machine-u: Inoćentije III. koristi rex, kralj: Calojoanni, illustri Bulgarorum et Blacorum regi ... regem te statuimus super eos, a Kalojan - imperator, car: Calojoannes, imperator Bulgarorum, sanctissimo domino, fidei Christianorum ab Oriente uque ad Occidentem patriarchae, papae Romano
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Pisma Inoćentija ІІІ.Arhivirano 2010-10-11 na Wayback Machine-u: Inoćentije III. koristi rex, kralj: Calojoanni, illustri Bulgarorum et Blacorum regi ... regem te statuimus super eos, a Kalojan - imperator, car: Calojoannes, imperator Bulgarorum, sanctissimo domino, fidei Christianorum ab Oriente uque ad Occidentem patriarchae, papae Romano
