@misc{indiciae2c93f76a7795,
  title = {The California poppy (eschscholtzia mexicana) as a copper indicator plant - A new example},
  author = {M.A. Chaffee and C.W. Gale},
  year = {1976},
  doi = {10.1016/0375-6742(76)90035-2},
  url = {https://pubs.usgs.gov/publication/70010233},
  note = {Source identifier: 70010233}
}