question: In quanti libri scritti da Dan Brown appare il personaggio del professore Robert Langdon?
answerText: 5
questionEntity.name: Q7345
questionEntity.entityType: entity
questionEntity.label: Dan Brown
questionEntity.name: Q210548
questionEntity.entityType: entity
questionEntity.label: Robert Langdon
answerEntity.name: Q182502
answerEntity.label: Angeli e demoni
answerEntity.name: Q81689
answerEntity.label: Il codice da Vinci
answerEntity.name: Q211006
answerEntity.label: Il simbolo perduto
answerEntity.name: Q4845793
answerEntity.label: Inferno
answerEntity.name: Q30610044
answerEntity.label: Origin