$pidEmpty = pp($tree->{drug}->{$i}->{'general-references'}->{articles}->{article});
	if ($pidEmpty eq "undef") {
	
	}else{
	$pidArray = $tree->{drug}->{$i}->{'general-references'}->{articles}->{article};
	}
	if (ref($pidArray) eq "ARRAY"){
	for $y (@{$tree->{drug}->{$i}->{'general-references'}->{articles}->{article}}){
	if ((ref($y) eq "HASH")){
	#print pp($y);
	#print "\n";
	$pid = $y->{'pubmed-id'};
	print "$pid\n";
	$pids = $pids . "$y,";
	}
	}
	}else{
	$pid = $pidArray->{'pubmed-id'};
	$pids = $pids . "$pid,";
	}
	$pids =~ s/,$//;