@book { TeachingSpivakOtherwise,
    title = "Teaching Spivak—Otherwise",
    author = "Jerry D. {Leonard}",
    year = "2019",
    publisher = "Peter Lang Verlag",
    address = "New York, United States of America",
    doi = "10.3726/b14971",
    url = "https://www.peterlang.com/document/1057804"
}