@article{PopovLiperovskyLiperovskayaetal.1996,
  author    = {K. V. Popov and Viktor A. Liperovsky and E. V. Liperovskaya and S. A. Senchenkov and Claudia-Veronika Meister},
  title     = {On weekly variations of the ionospheric foF2-frequency possibly caused by anthropogenic activity},
  year      = {1996},
}