BibTeX

@ARTICLE{iumj21018,
    author = "R. Redheffer",
     title = "The Sharp Maximum Principle for Nonlinear Inequalities",
   journal = "Indiana Univ. Math. J.",
  fjournal = "Indiana University Mathematics Journal",
    volume = 21,
      year = 1972,
     issue = 3,
     pages = "227--248",
      issn = "0022-2518",
     coden = "IUMJAB",
   mrclass = "",
}

amsrefs

\bib{iumj21018}{article}{
     author = {Redheffer, R.},
      title = {The Sharp Maximum Principle for Nonlinear Inequalities},
    journal = {Indiana Univ. Math. J.},
     volume = {21},
       year = {1972},
     number = {3},
      pages = {227 \ndash 248},
}