BibTeX

@ARTICLE{iumj26030,
    author = "Robert Kohn",
     title = "An Example Concerning Approximate Differentiation",
   journal = "Indiana Univ. Math. J.",
  fjournal = "Indiana University Mathematics Journal",
    volume = 26,
      year = 1977,
     issue = 2,
     pages = "393--397",
      issn = "0022-2518",
     coden = "IUMJAB",
   mrclass = "",
}

amsrefs

\bib{iumj26030}{article}{
     author = {Kohn, Robert},
      title = {An Example Concerning Approximate Differentiation},
    journal = {Indiana Univ. Math. J.},
     volume = {26},
       year = {1977},
     number = {2},
      pages = {393 \ndash 397},
}