#!/usr/bin/perl

use strict;
use warnings;

use XML::Twig;

my $twig= new XML::Twig(
	twig_handlers => {
        CS_REFCLT          => \&cs_refclt,
	},
);

my @numbers;

$twig->parsefile( 'filename' );
# here you will have all numbers in @numbers.


sub cs_refclt {
	my ($t, $elt)= @_;
	push @numbers, $elt->text();
}