Per anno

@book{frege-foundations1971,
    address = {New Haven, CT, USA},
    apice = {FregeFoundations1971},
    author = {Gottlob Frege},
    isbn10 = {0300013930},
    isbn13 = {9780300013931},
    note = {Translated by Eike-Henner W. Kluge},
    publisher = {Yale University Press},
    title = {On the Foundations of Geometry and Formal Theories of Arithmetic},
    url = {https://philpapers.org/rec/FREOTF-4},
    year = 1971
}

@article{dennet-intentionalsystems71,
    apice = {DennettIntentionalSystems1971},
    author = {Dennett, Daniel},
    journal = {The Journal of Philosophy},
    month = feb,
    number = 4,
    pages = {87--106},
    title = {Intentional Systems},
    url = {https://www.pdcnet.org/jphil/content/jphil_1971_0068_0004_0087_0106},
    volume = 68,
    year = 1971
}