V. Naydenov, N. Torbov
Roman and late antique lamps from the collection of Regional Historical Museum in Pleven
in: Ηρακλεoυς Σωτηρoς θασιων. Izsledvanija v cest na Ilja Prokopov ot prijatelite i ucenicite mu po slucaj negovta 60 godišnina. Studia in honorem Iliae Prokopov sexagenario ab amicis et discipulis dedicata, Tirnovo 2012, pp. 769-790.