Soviet DDSG vessels ordered to bear the designation SDDSG-Port Vienna in cyrillic letters according to a CIA report dated 29 March 1955

An item reported that from 20 January 1955 all Soviet DDSG (Sowjetische Donau Dampf Schiffahrts Gesellschaft m.b.H.) vessels were ordered to bear the designation SDDSG-Port Vienna in cyrillic letters.

Source
The report was published on www.archive.org, document number CIA-RDP80-00810A006200800008-0