US CONGRESS LIBRARY AND RUSSIA'S MARIINSKY THEATRE INTEND TO COOPERATE WASHINGTON, March 11, 2001. /From RIA Novosti correspondent Arkady Orlov/. Librarian of the US Congress James Billington and Director of St. Petersburg's Mariinsky Theatre Valery Gergiyev will meet in Washington on March 30 to sign an agreement concerning the storage of a St. Petersburg-based collection of opera scores. According to the document, the sides are to join efforts to compile a catalogue and take microfilms of the unique collection of opera scores and other music sheets assembled by the employees of the famous Russian theatre over the years of its existence. The US Congress Library, considered the world's largest depositary of books, films and music scores, will help the Russian side make up a catalogue of the collection and take care of its storage. On its part, Russia will let experts from the United States and other countries use copies of its microfilmed materials. The Mariinsky's collection of opera scores has grown into a "real treasure-house" since the times when Russian tsars started it, but now it needs to be arranged and systematized, says Billington. Experts of the US Congress Library have already done a preliminary expert review of the materials stored in St. Petersburg.