It is a very early Satsuma created in Croatia.
http://www.exotickerostliny.cz/cs/katalog-rostlin-othermenu-95/citrusy-othermenu-90/72-mandarina-unshiu-citrus-unshiu.html
Google translation:
The Croatian very early variety produced in the 70 years in school in Opuzen, where she found Dr. ivko Gatinem as pupenová mutation mandarin 'Kawana. Was named according to nálezkyně and ranosti Zorica - rana. Matures three weeks earlier than the parent plant in mid-September (in our matures in pots in a cold greenhouse around 20 October). Tree height of more than 2 ms spread overhanging crown. Leaves with slender laminate, about 7-10 cm long, similar foliage varieties' Kawana. It has a very high fertility, the fruits of the average weight of 80 g oval, flattened, pericarp color orange-yellow, smooth, well loupatelné in drinking maturity, there is still some greenish. The flesh is pale orange, juicy, refreshing as most of the very early mandarin uniu dominated acids over sugars. Suitable for residential as well as greenhouse cultivation. Due to the large ranosti achieve high quality fruit in our conditions (adequate temperature and light at the time of maturation).
And pictures from Petr: