use warnings;
use strict;

my $str = <<TEXT;
All businesses, regardless of their size, location, or mission, operate within a
larger external environment. This external environment consists of everything
outside an organization&#146;s boundaries that might affect it. Not
surprisingly, the external environment plays a major role in determining the
success or failure of any organization. Managers must therefore have a complete
and accurate understanding of their environment and then strive to operate and
compete within it. Of course, businesses can also influence their environments.
To better explain the environment of business, we begin by discussing
organizational boundaries, and then we introduce the concept of multiple
organizational environments. Quite simply, an organizational boundary is that
which separates the organization from its environment.<fref id="fn1"/> But
whereas boundaries were once relatively easy to identify, they are becoming
increasingly complicated and hard to pin down. Consider the simple case of a
small neighborhood grocery that includes a retail customer area, a storage room,
and an owner/manager&#146;s office.<fref id="fn2"/> In many ways, the
store&#146;s boundary coincides with its physical structure: When you walk
through the door, you&#146;re crossing the boundary into the business, and when
you go back onto the sidewalk, you cross the boundary back into the
environment.<fn id="fn1">See Waren J. Keegan, Global Marketing
Management</fn><fn id="fn2">See James J. Kellenberger, Global Warming
Management</fn>
TEXT

my @footnotes;

push @footnotes, [$1, $2] while $str =~ m|<fn\s+id="(\w+)">((?:(?!</fn>).)*)</fn>|gms;

$str =~ s|
    <fref\s+id="\Q$_->[0]\E"/>
    |
    <footnote id="$_->[0]"$_->[1]<\/para><\/footnote>
    |gxms
    for @footnotes;
print $str;