BibTeX

@ARTICLE{iumj2286,
    author = "H. Langer and M. Langer and Christiane Tretter",
     title = "Variational principles for eigenvalues of block operator matrices",
   journal = "Indiana Univ. Math. J.",
  fjournal = "Indiana University Mathematics Journal",
    volume = 51,
      year = 2002,
     issue = 6,
     pages = "1427--1460",
      issn = "0022-2518",
     coden = "IUMJAB",
   mrclass = "",
}

amsrefs

\bib{iumj2286}{article}{
     author = {Langer, H.},
     author = {Langer, M.},
     author = {Tretter, Christiane},
      title = {Variational principles for eigenvalues of block operator matrices},
    journal = {Indiana Univ. Math. J.},
     volume = {51},
       year = {2002},
     number = {6},
      pages = {1427 \ndash 1460},
}