@book{
  international1968iaea,
  title={Theory of Condensed Matter (Trieste, 3 Oct. - 18 Dec. 1967)},
  series={Proceedings Series},
  year={1968},
  isbn={92-0-130068-9},
  url={https://www.iaea.org/publications/2178/theory-of-condensed-matter-trieste-3-oct-18-dec-1967},
  publisher={INTERNATIONAL ATOMIC ENERGY AGENCY},
  address={Vienna}
}