@book{ashcroft1976,
  title={Solid State Physics},
  author={Ashcroft, Neil W. and Mermin, N. David},
  year={1976},
  publisher={Saunders College Publishing}
}

@book{bruus2004,
  title={Many-Body Quantum Theory in Condensed Matter Physics: An Introduction},
  author={Bruus, Henrik and Flensberg, Karsten},
  year={2004},
  publisher={Oxford University Press},
  address={Oxford}
}