@misc{indiciaed54ee1957194,
  title = {Electron-bombardment thrusters using liquid- mercury cathodes.},
  author = {Eckhardt, W. O. and King, H. J. and Knechtli, R. C. and Ward, W.},
  year = {1966},
  url = {https://ntrs.nasa.gov/citations/19660045882},
  note = {Source identifier: 19660045882}
}