BibTeX

@ARTICLE{iumj21076,
    author = "P. Halmos",
     title = "Positive Approximants of Operators",
   journal = "Indiana Univ. Math. J.",
  fjournal = "Indiana University Mathematics Journal",
    volume = 21,
      year = 1972,
     issue = 10,
     pages = "951--960",
      issn = "0022-2518",
     coden = "IUMJAB",
   mrclass = "",
}

amsrefs

\bib{iumj21076}{article}{
     author = {Halmos, P.},
      title = {Positive Approximants of Operators},
    journal = {Indiana Univ. Math. J.},
     volume = {21},
       year = {1972},
     number = {10},
      pages = {951 \ndash 960},
}