BibTeX

@ARTICLE{iumj18064,
    author = "Ivor Robinson and James Robinson and Joseph Zund",
     title = "Degenerate Gravitational Fields with Twisting Rays",
   journal = "Indiana Univ. Math. J.",
  fjournal = "Indiana University Mathematics Journal",
    volume = 18,
      year = 1969,
     issue = 9,
     pages = "881--892",
      issn = "0022-2518",
     coden = "IUMJAB",
   mrclass = "",
}

amsrefs

\bib{iumj18064}{article}{
     author = {Robinson, Ivor},
     author = {Robinson, James},
     author = {Zund, Joseph},
      title = {Degenerate Gravitational Fields with Twisting Rays},
    journal = {Indiana Univ. Math. J.},
     volume = {18},
       year = {1969},
     number = {9},
      pages = {881 \ndash 892},
}