@conference{4764,
  author = {Leonid Grishchuk},
  title = {Primordial gravitational waves},
  year = {1991},
  publisher = {Societa Italiana di Fisica, Bologna, Italy},
  address = {Rome, Italy},
  isbn = {088-7794-069-7},
  note = {JILA Pub. 4464},
}