Columbia subject headings:
Bolu (Turkey)--Civilization--Congresses.
Bolu (Turkey)--History--Congresses.
Köroğlu, active 16th century--Congresses.
Harvard subject headings:
Bolu (Turkey)--Civilization--Congresses.
Bolu (Turkey)--History--Congresses.
Köroğlu, active 16th century--Congresses.
Princeton subject headings:
Bolu (Turkey)--Civilization--Congresses.
Bolu (Turkey)--History--Congresses.
Köroğlu, active 16th century--Congresses.