@misc{indiciaecfbd662043ca,
  title = {Element levels in selected soils and plants, Wattenmeer National Park, North and East Frisian Islands, Federal Republic of Germany},
  author = {R. C. Severson and L. P. Gough and G. van den Boom},
  year = {1990},
  doi = {10.3133/ofr90493},
  url = {https://pubs.usgs.gov/publication/ofr90493},
  note = {Source identifier: ofr90493}
}