The global 2000 report to the president of the U.S. : entering the 21st century : special edition with the environment projections and the government's global model (engelsk)
Miniatjuri ot Madridskija r kopis na Joan Skilica: izsledvane v rchu miniatjurite ot rakopisa na Joan Skilica ot XII-XIII vek v Madridskata nacionalna biblioteka (bulgarsk)
Miniatjuri ot Madridskija rakopis na Joan Skilica : izsledvane varchu miniatjurite ot rakopisa na Joan Skilica ot XII-XIII vek v Madridskata nacionalna biblioteka (bulgarsk)