@other{https://resolver.caltech.edu/CaltechAUTHORS:20190219-123239808,
    title = "Nonlinear Equations Describing Beam Type Crossed Field Traveling Wave Tubes",
    url = "https://resolver.caltech.edu/CaltechAUTHORS:20190219-123239808",
    id = "record",
    doi = "10.7907/71ZR-ZY80"
}