@phdthesis{Brehm2009,
  author      = {Sascha Brehm},
  title       = {Two-Particle Excitations in the Hubbard Model for High-Temperature Superconductors: A Quantum Cluster Study},
  type        = {doctoralthesis},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year        = {2009},
}