@other{https://resolver.caltech.edu/CaltechETD:etd-09162008-105121,
    title = "The relationship between the density wave, molecular gas and star formation in M51",
    year = "1991",
    url = "https://resolver.caltech.edu/CaltechETD:etd-09162008-105121",
    id = "record",
    doi = "10.7907/c2j4-qh42"
}