BibTeX

@ARTICLE{iumj20011,
    author = "Gerald Porter",
     title = "On the Commutativity of Homotopy Groups",
   journal = "Indiana Univ. Math. J.",
  fjournal = "Indiana University Mathematics Journal",
    volume = 20,
      year = 1971,
     issue = 2,
     pages = "113--114",
      issn = "0022-2518",
     coden = "IUMJAB",
   mrclass = "",
}

amsrefs

\bib{iumj20011}{article}{
     author = {Porter, Gerald},
      title = {On the Commutativity of Homotopy Groups},
    journal = {Indiana Univ. Math. J.},
     volume = {20},
       year = {1971},
     number = {2},
      pages = {113 \ndash 114},
}