LIBRARY OF THE CONGRESS OF USA AND RUSSIA MARIINSKI THEATRE WOOLS COOPERATING WASHINGTON, 11 March (of RIA Nowosti rIA-Nowosti-Korrespondent Arkadi Orlow). The director of the library of the USA congress, James Billington, and the director of the Mariinski theatre of St. Petersburg, Valeri Gergijew, will sign an agreement on 30 March over co-operation during the maintenance of the unique collection of opera scores of the theatre. The agreement designates the composition of a catalog and a copying of the rare scores as well as from notes of other music factories, which were collected in the years of the existence of the theatre, on microfilms. The library of the USA congress, which is considered as the world largest collection of books, films and music scores, will supply its experts for this work. In the exchange for it the music researchers from the USA and other countries the right are gotten to use the microfilm copies of the Russian Materialen. As James Billington before journalists explained, the collection of opera scores of the Mariinski theatre was " a genuine treasure ". The collection was created on statement of Russian Zaren, today however the necessity developed to list this collection accurately and in modern way.