My codes are not working (json, arrays)

$wiki_img = "http://ift.tt/1ckD1KK";

$json2 = file_get_contents($wiki_img);
$data2 = json_decode($json2, TRUE);

foreach ($data2['query']['pages'] as $pages) {
print_r($pages['source']);
}

My codes are not working. But I can't find what is error.I got this error "Notice: Undefined index: source in C:\xampp\htdocs\"