Informazzjoni minn organizzazzjoni tal-arti (Verifikat minn Operabase)
150 Years Bulgarian Academy of Sciences by Vladigerov, P., Cherkin, Stainov, Stoyanov, Dinicu, G., Minn (2019/2019), Surmast Direttur Nayden Todorov, The National Palace of Culture - Congress Centre Sofia (NDK), Sofia, Bulgaria