//-->
Pogled kŭm stopanskija z̆ivot i stopanskata kultura na prabŭlgarite predi tjachnata migracija kŭm Evropa
Dobrev, Petǔr, (1981)
The people of Asia
Bowles, Gordon T., (1977)
The early Middle Ages in the West
Doehaerd, Renée, (1978)