Untested, (no AppID)Tested, based on Bing::Search::Source::Web:

use strict;
use Bing::Search;
use Bing::Search::Source::Web;
my $search = Bing::Search->new(
  AppId => 'my ID',
  Query => 'Inflation site:europa.eu language:de filetype:pdf',
);
my $source = Bing::Search::Source::Web->new(
  Web_Count => 50,
  Web_Offset => 0,
);
$search->add_source( $source );
my $response = $search->search();
print $_->Url ."\n" for @{$response->results};
[download]

Updated - got AppId, fixed code