Megalitite v Trakii͡a - Venedikov, Ivan J.; Fol, Aleksandŭr, 1933-2006 (Izd-vo Nauka i izkustvo, 1976)
Title on verso of t.p.: Megalithi thraciae.
On leaf preceding t.p., volume 1-Institut po trakologii͡a pri BAN; volume 3- Institut po Trakologii͡a pri BAN. Nat͡sionalen istoricheski muzeĭ.
Summary in English, French, and Russian.