{ intro: isoxml.at(ns("//bibdata/title[@type='title-intro' and " \
                              "@language='#{lang}']")),
          main: isoxml.at(ns("//bibdata/title[@type='title-main' and " \
                             "@language='#{lang}']")),
          part: isoxml.at(ns("//bibdata/title[@type='title-part' and " \