@book{PettersLevineWambsganss2001,
  author    = {Petters, Arlie O. and Levine, Harold and Wambsganß, Joachim},
  title     = {Singularity theory and gravitational lensing},
  series = {Progress in mathematical physics},
  volume    = {21},
  journal   = {Progress in mathematical physics},
  publisher = {Birkh{\"a}user},
  address   = {Boston},
  isbn      = {0-8176-3668-4},
  pages     = {XXIV, 603 S. : Ill., graph. Darst.},
  year      = {2001},
  language  = {en}
}