@misc{indiciae59da75012347,
  title = {Philadelphia region input-output study working papers. Volume 3 - Final demand},
  author = {Isard, W. and Langford, T. W., Jr.},
  year = {1968},
  url = {https://ntrs.nasa.gov/citations/19680017282},
  note = {Source identifier: 19680017282}
}