@article{Konacki:2000,
  author  = "M. Konacki and A. Maciejewski and A. Wolszczan",
  title   = "Improved timing formula for the PSR B1257 + 12 planetary system",
  journal = "Astrophysical Journal",
  number  = "no 544",
  pages   = "921--926",
  year    = "2000",
}