@article{Cao:2000,
  author  = "Z. Cao and A. Grytczuk",
  title   = "Some classes of Diophantine equations connected with McFarland's and Ma's conjectures",
  journal = "Discussiones Mathematicae : General Algebra and Applications",
  volume  = "Vol. 20",
  number  = "no 2",
  pages   = "193--198",
  year    = "2000",
}