Bulgaria 1951 Leningrad mints [solved]

I've got that info from the secretary of Sofia Numismatic Society. He told me that first minted coins from that year have been minted in Leningrad and they are much rare than these which are minted in Sofia. The major differences are that the star of the coat of arms is bigger and closer to the circle and the lion's mane is bigger and covers the arm. For now I know only for that coin, will see will I find more info about the other values.