@book{SchmidtBadtkeBittmannetal.1998,
  author    = {Schmidt, Marco and Badtke, Gernot and Bittmann, Frank and Steuer, M.},
  title     = {A new approach for objektive determination of the external spine profile in the sagittal plane},
  year      = {1998},
  language  = {en}
}
@article{BadtkeBittmannSchmidtetal.1997,
  author    = {Badtke, Gernot and Bittmann, Frank and Schmidt, Marco and Steuer, M},
  title     = {Ein neues Verfahren zur objektiven Bestimmung der {\"a}ußeren Wirbels{\"a}ulenkurvatur in der Sagittalebene},
  year      = {1997},
  language  = {de}
}