@article{Urbanowski:1993,
  author  = "K. Urbanowski",
  title   = "Early time properties of time evolution in two-dimensional subspace and CP violation problem",
  journal = "International Journal of Modern Physics A",
  volume  = "Vol. 8",
  number  = "no 21",
  pages   = "3721--3745",
  year    = "1993",
}