@article{Więckowski:1998,
  author  = "A. Więckowski and B. Pilawa and M. Lewandowski and W. Wojtowicz and G. Słowik",
  title   = "Paramagnetic centres in exinite, vitrinite and inertinite",
  journal = "Applied Magnetic Resonance",
  volume  = "Vol. 15",
  number  = "no 3-4",
  pages   = "489--501",
  year    = "1998",
}