@misc{indiciaeb8ce52edab15,
  title = {Photovoltaic module soiling studies, May 1978 - October 1980},
  author = {Hoffman, A. R. and Maag, C. R.},
  year = {1980},
  url = {https://ntrs.nasa.gov/citations/19810008062},
  note = {Source identifier: 19810008062}
}