In Slovakia (former Czechoslovakia) and Czech republic, there are many citrus varieties from the era of former USSR. I think there were citrus breeding and research stations in Gulripshi (Abkhazia) and Sotchi and Green Cape Batumi (Georgia).

Some citrus varieties from former USSR:

lemons:
Abchazskij
Baku n.14
Dortiolskij
Jubylejnij
Kusner
Limonovij
Majkopskij
Pavlovskij
Taskentskij
Udarnik 2989 any many others

oranges:
Koroljok no.13
Adarskij
Suchumskij
Gagra
Kelasurskij
Slava Micurina
etc.

unshiu mandarins and hybrids:

Abchazuri
Aurelia
Kalinin no.5
Grusevydnij (means pear-shaped)
Cartuli
Pionier no.80
Skorospielij (means "early")
Slava Vavilova
Sotchi I, Sotchi II
Sirokolistvenyj (means wide-leaf)

and many others.

Very interesting Radoslav,

how is the cold resistence? I presume it will not be very warm in wintertime in the Chech republic and in the rest of the former USSR?
And do you know if these varieties are for sale (and where)?

Greetings
Max

Oh no , they aren't outdoor in Slovakia or Czech republic, they are in the temperated greenhouses in private collections. Most of SR or CR is in zone 6. Some of them you can buy here: www.exotickerostliny.cz
In USSR, they were grown in coastal area of Georgia and also in Uzbekistan.

http://hrcak.srce.hr/index.php?show=clanak&id_clanak_jezik=78053

I think, that Ichimaru and Zorica Rana look VERY similary ...