@article{Drab:2010,
  author  = "M. Drab and A. Greinert",
  title   = "Calcium content in post-mining grounds in the Łęknica Region",
  journal = "Civil and Environmental Engineering Reports",
  volume  = "no 4",
  pages   = "46--57",
  year    = "2010",
  note    = "University of Zielona Góra Press, Zielona Góra",
}