A libretto can be known.Logical formLearned from2 sentences. Complaints can be about a libretto.Logical formLearned from2 sentences. A book may contain a libretto.Logical formLearned from2 sentences. A subject may pertain-to a libretto.Logical formLearned from2 sentences. Librettos can be published.Logical formLearned from2 sentences. A libretto may pertain-to a world-city.Logical formLearned from2 sentences. A libretto may be based on a novel.Logical formLearned from2 sentences. An one may make a libretto of a play.Logical formLearned from2 sentences. A libretto may be based on a play of a name.Logical formLearned from2 sentences. A male may hand a libretto.Logical formLearned from2 sentences. A libretto can be by playwright.Logical formLearned from2 sentences. An act can be by a male to a libretto.Logical formLearned from2 sentences. Some librettos can be for a male.Logical formLearned from2 sentences. A libretto may be based on a book.Logical formLearned from2 sentences. An inspiration can be for some passages of a libretto.Logical formLearned from2 sentences.