@book { AstudyofecolabellinginSpainandtourismdecisionmaking,
    title = "A study of eco-labelling in Spain and tourism decision making",
    author = "Lisa {Sitnikow}",
    year = "2010",
    publisher = "Diplom.de",
    address = "Hamburg, Deutschland",
    doi = "10.3239/9783836643849",
    url = "https://m.diplom.de/document/227657"
}