The merchant shipping between Bulgaria, Albania and the Soviet Union according to a CIA report dated 4 September 1953

An item reported that ships on the line Bulgaria-Albania transported grain, pig iron, light machinery and Czech trucks and on the way back asphalt and ore. Sometimes were machinery direct shipped from the Soviet Union to Albania or asphalt and ore directly from Albania towards the Soviet Union.

Source
The report was published on www.archive.org, document number CIA-RDP80-00810A002200170042-3