@article{https://resolver.caltech.edu/CaltechAUTHORS:FULpnas71,
    title = "The writhing number of a space curve",
    journal = "Proceedings of the National Academy of Sciences of the United States of America",
    year = "1971",
    url = "https://resolver.caltech.edu/CaltechAUTHORS:FULpnas71",
    id = "record",
    issn = "0027-8424",
    volume = "68"
}