@phdthesis{Ludwig2017,
  author      = {Marie-Isabel Ludwig},
  title       = {Assessing Soil Organic Matter by Combining Non-Invasive (Spectroscopic) and Invasive Methods},
  type        = {doctoralthesis},
  school      = {Universit{\"a}t Trier},
  doi       = {10.25353/ubtr-xxxx-c42b-137b},
  year        = {2017},
}