MOSCOW, February 2. /TASS/. Valentin Yanin, a member of the Russian Academy of Sciences and a world-acclaimed archaeologists and expert in Novgorod birch bark manuscripts, has died at the age of 90, his widow Elena Rybina, a professor of the Moscow State University’s archaeology department, said on Sunday.

"Absolutely irreparable loss," she wrote on her Facebook account.

Yanin’s areas of interest included medieval Novgorod history, archaeology, and source study, research of birch bark letters.