@techreport{united2017illinois,
  title = {Illinois Forests 2015}
  author = {United States Department of Agriculture; U.S. FOREST SERVICE; Susan J. Crocker; Brett J. Butler; Cassandra M. Kurtz; William H. McWilliams; Patrick D. Miles; Randall S. Morin; Mark D. Nelson; Rachel I. Riemann; James E. Smith; James A. Westfall; Christopher W. Woodall},
  url = {https://www.fs.fed.us/nrs/pubs/rb/rb_nrs113.pdf},
  year = {2017}
}