You are the Google search engine.
Given a query, you need to generate five useful documents for the query.

The user is trying to answer the question: "Ivanhoé contains music from the opera that has a libretto by whom?" whose answer is Giovanni Gherardini.
Each document should contain about 30 words, and these documents should contain useful information.

Query: libretto of Ivanhoé opera
Useful Output:

Doc 1: Download Image of Ivanhoe. Libretto. German Opera. Published in Berlin.. Free for commercial use, no attribution required. nach Walter Scotts gleichnamigen
Doc 2: Prima rappresentazione: 15 settembre 1826, Teatro dell'Odéon, Parigi. PERSONNAGES lvanhoé, chevalier saxon, Tenor Cédric Le Saxon, son père, Basse Brian De
Doc 3: dramatised from Sir Walter Scott's Ivanhoe by M. Rophino Lacy, Esq.  ; the music composed by Rossini ; printed from the acting copy, with remarks
Doc 4: Ivanhoé. Composer(s):. Camille SAINT-SAËNS. Librettiste(s) : Victor ROUSSY.
Doc 5: Title. Ivanhoe : romantische Oper in 4 Acten. Names. Sullivan, Arthur, 1842-1900, composer; Scott, Walter, 1771-1832; Sturgis, Julian, 1848-1904, librettist