Mon May 20, 2013 8:56am EDT
(Adds details, effects of financial crisis on Hellenic)
LONDON May 20 (Reuters) - Hellenic Petroleum, Greece's largest refiner, has issued a tender to buy an 80,000 tonne cargo of Russian Urals crude oil for early June delivery, a trading source said, the first in months as its finances improve.
The tender was issued on Friday and closes today. The payment will be ...