@article{https://resolver.caltech.edu/CaltechAUTHORS:NGUjam80,
    title = "Funnel Flow in Hoppers",
    journal = "Journal of Applied Mechanics",
    year = "1980",
    url = "https://resolver.caltech.edu/CaltechAUTHORS:NGUjam80",
    id = "record",
    issn = "0021-8936",
    volume = "102"
}


@article{https://resolver.caltech.edu/CaltechAUTHORS:NGUjam79,
    title = "Gravity Flow of Granular Materials in Conical Hoppers",
    journal = "Journal of Applied Mechanics",
    year = "1979",
    url = "https://resolver.caltech.edu/CaltechAUTHORS:NGUjam79",
    id = "record",
    issn = "0021-8936",
    volume = "46"
}