@book{
  author = "Spring School on Superstrings, Harvey, Jeffrey A, Iengo, R, Narain, K. S., Randjbar-Daemi, S., Verlinde, H.",
  title = "String theory and quantum gravity '91 : proceedings of the Trieste Spring School & Workshop, ICTP, Trieste, Italy, April 15-26, 1991",
  year: c1992
  key = "String models--Congresses",
  key = "Superstring theories--Congresses",
  key = "Quantum gravity--Congresses",
  publisher = "World Scientific",
  address = "Singapore",
  ISSN/ISBN = "9789810207748 [9810207743]",
}