Per anno

@article{shannon1948ii,
    apice = {Shannon1948II},
    author = {Claude E. Shannon},
    doi = {10.1002/j.1538-7305.1948.tb00917.x},
    issn = {0005-8580},
    journal = {The Bell System Technical Journal},
    month = oct,
    note = {Part II of a paper published in two parts, July and October 1948.},
    number = 4,
    numpages = 34,
    pages = {623--656},
    title = {A Mathematical Theory of Communication},
    url = {https://people.math.harvard.edu/~ctm/home/text/others/shannon/entropy/entropy.pdf},
    volume = 27,
    year = 1948
}

@article{shannon1948i,
    apice = {Shannon1948I},
    author = {Claude E. Shannon},
    doi = {10.1002/j.1538-7305.1948.tb01338.x},
    issn = {0005-8580},
    journal = {The Bell System Technical Journal},
    month = jul,
    note = {Part I of a paper published in two parts, July and October 1948},
    number = 3,
    numpages = 45,
    pages = {379--423},
    title = {A Mathematical Theory of Communication},
    url = {https://people.math.harvard.edu/~ctm/home/text/others/shannon/entropy/entropy.pdf},
    volume = 27,
    year = 1948
}