@book { AnInquiryonModalMetaphysicalPuzzlingPossibleWorlds,
    title = "An Inquiry on Modal Metaphysical Puzzling Possible Worlds",
    author = "Valery {Berthoud}",
    year = "2017",
    publisher = "Anchor Academic Publishing",
    address = "Hamburg, Germany",
    url = "https://m.anchor-publishing.com/document/375506"
}