@misc{indiciae17dca1c135bd,
  title = {The International GPS Service (IGS) as a Continuous Reference System for Precise GPS Positioning},
  author = {Neilan, Ruth and Heflin, Michael and Watkins, Michael and Zumberge, James},
  year = {1996},
  url = {https://ntrs.nasa.gov/citations/20060036040},
  note = {Source identifier: 20060036040}
}