@misc{indiciaedd3f05a5475e,
  title = {Spectral factorization in time-varying systems having periodic coefficients and its application to navigation of solar electric interplanetary missions},
  author = {Nishimura, T.},
  year = {1971},
  url = {https://ntrs.nasa.gov/citations/19710062366},
  note = {Source identifier: 19710062366}
}