@book { JohannJuliusWilhelmPlanck18171900,
    title = "Johann Julius Wilhelm Planck (1817–1900)",
    author = "Tanja {Claussen}",
    year = "2015",
    publisher = "Peter Lang Verlag",
    address = "Berlin, Germany",
    doi = "10.3726/978-3-653-05330-2",
    url = "https://www.peterlang.com/document/1049114"
}