@article{Karczewska:2017,
  author  = "A. Karczewska and P. Rozmej and E. Infeld and G. Rowlands",
  title   = "Adiabatic invariants of the extended KdV equation",
  journal = "Physics Letters A",
  volume  = "Vol. 381",
  number  = "iss. 4",
  pages   = "270--275",
  year    = "2017",
}