@inproceedings{1015889,
    title = "Pythagorean persons",
    author = "Purtill, Richard L.",
    year = "1992",
    pages = "163-170",
    publisher = "Διεθνές Κέντρον Ελληνικής Φιλοσοφίας και Πολιτισμού",
    booktitle = "Pythagorean philosophy"
}