@misc{indiciaed0ee4d3d5e0a,
  title = {Estimation of internal source distributions using external field measurements in radiative transfer.},
  author = {Bellman, R. E. and Kagiwada, H. H. and Kalaba, R. E.},
  year = {1966},
  url = {https://ntrs.nasa.gov/citations/19660053722},
  note = {Source identifier: 19660053722}
}