Apparently you want to get the Wikipedia link through a correct Google search?
Well, I just created and tested a solution for you, maybe not one of the best, however it works! :D
<?
    $TermoDeBusca = urlencode('ASP World Tour'); // Termo de Busca
    // Curl! 
    $ch = curl_init ("");
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, TRUE);
    curl_setopt($ch, CURLOPT_URL, 'https://www.google.com/search?q='.$TermoDeBusca);
    curl_setopt($ch, CURLOPT_USERAGENT, 'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.95 Safari/537.36'); 
    $html = curl_exec($ch);
    // DOM!
    $dom = new DOMDocument;
    $dom->loadHTML($html);
    $xpath = new DOMXPath($dom); 
    $items = $xpath->query("//h3[contains(@class, 'r')]//a"); //Pega dentro do <H3> (de classe 'r') o valor do <a>
        foreach ($items as $pega){ // Loop, para cada link
            $link = $pega->getAttribute('href'); // Será: http://pt.wikipedia.org/wiki/ASP_World_Tour
                if (strpos($link,'wikipedia.org') == true) { // Verifica se o $link contem o 'wikipedia.org', ou seja, se é do wikipedia ~~ gambiarra
                echo $link.'<br>'; // se for, ele mostra o link
                } // fimse
        } //fim do foreach
?>
I tried to comment as much as I could, unfortunately I don’t have time for that.
I did what I could! D
							
							
						 
Hey, which regex could I use to find a wikipedia url? I was trying with one of these
(.*).wikipedia.org\/wiki\/(.*)[ ]+– Vinícius Lara
@user3163662 This will depend on what you are doing, a Regex may not even be the ideal shape. Open a question with an example of the code and it will be easy to help.
– Zuul