@article{Szajna:2015,
  author  = "W. Szajna and A. Gontaszewska-Piekarz",
  title   = "Shallow site investigation of Quaternary sands inside and in the vicinity of a sinkhole in the former lignite mining area in Zielona Góra (western Poland)",
  journal = "Geological Quarterly",
  volume  = "Vol. 59",
  number  = "no. 2",
  pages   = "347--357",
  year    = "2015",
}