Reference for “XHTML™ 1.1 - Module-based XHTML”

@TechReport{Altheim:01:XMX,
  author      = "Murray Altheim and Shane McCarron",
  title       = "{XHTML}\texttrademark{} {1.1} - Module-based {XHTML}",
  month       = may,
  note        = "http://www.w3.org/TR/2001/REC-xhtml11-20010531",
  year        = "2001",
  bibsource   = "http://w2.syronex.com/jmr/w3c-biblio",
  type        = "{W3C} Recommendation",
  institution = "W3C",
}