sub getSubjects($)
{
my $ref_sRecord = $_[0];
my @aSubNos = $$ref_sRecord =~ m/<subno>(.+?)<\/subno>/sig;
....
}

##</code><code>##

....
<level>1</level>
<subject>
<subno>2.1.c</subno>
<subtxt>Subject 1</subtxt>
<subno>2.2</subno>
<subtxt>Subject 2</subtxt>
</subject>
....

##</code><code>##

my @aSubNos = $$ref_sRecord =~ m/<subno>(.+?)<\/subno>/sig;

##</code><code>##

my $sString = $$ref_sRecord;
my @aSubNos = $sString =~ m/<subno>(.+?)<\/subno>/sig;