@phdthesis{Groetzner2018,
  author      = {Patrick Hermann Groetzner},
  title       = {A Method for Completely Positive and Nonnegative Matrix Factorization},
  type        = {doctoralthesis},
  school      = {Universit{\"a}t Trier},
  doi       = {10.25353/ubtr-xxxx-37f5-ecec},
  year        = {2018},
}