@misc{indiciaec25b4d752e11,
  title = {Ripple add and ripple subtract binary counters Patent},
  author = {Cliff, R. A. and Schaefer, D. H.},
  year = {1970},
  url = {https://ntrs.nasa.gov/citations/19710009127},
  note = {Source identifier: 19710009127}
}