@misc{indiciaeb561e578f9a7,
  title = {Spring onset variations and trends in the continental United States: past and regional assessment using temperature-based indices},
  author = {Mark D. Schwartz and Toby R. Ault and Julio L. Betancourt},
  year = {2012},
  doi = {10.1002/joc.3625},
  url = {https://pubs.usgs.gov/publication/70039016},
  note = {Source identifier: 70039016}
}