@misc{indiciaeb7722ccad29d,
  title = {Simultaneous two channel frequency analyzer with non-electronic (passive) filters.},
  author = {M MEISTER and R S SCHWAB and E PETERSEN and A GRASS},
  year = {1959},
  doi = {10.1016/0013-4694(59)90063-x},
  url = {https://pubmed.ncbi.nlm.nih.gov/13663836/},
  note = {Source identifier: 13663836}
}