1.Official Tourism Portal of Bulgaria : http://bulgariatravel.org/ 2.Bulgaria : http://en.wikipedia.org/wiki/Bulgaria 3.Old Great Bulgaria : http://en.wikipedia.org/wiki/Old_Bulgaria 4.Volga Bulgaria : http://en.wikipedia.org/wiki/Volga_Bulgaria 5.First Bulgarian Empire : http://en.wikipedia.org/wiki/First_Bulgarian_Empire 6.Thracians : http://en.wikipedia.org/wiki/Thracians 7.Bulgars : http://en.wikipedia.org/wiki/Bulgars 8.Kingdom of Balhara : http://en.wikipedia.org/wiki/Kingdom_of_Balhara 9.Odrysian kingdom : http://en.wikipedia.org/wiki/Odrysian_kingdom 10.Sozopol : http://en.wikipedia.org/wiki/Sozopol