@book { FitnessTrainerBLizenz,
    title = "Fitness-Trainer B-Lizenz",
    author = "Harald {Schwimmer}",
    year = "2004",
    publisher = "GRIN Verlag",
    address = "München, Germany",
    doi = "10.3239/9783638295895",
    url = "https://www.hausarbeiten.de/document/27577"
}