Request.ServerVariables in function
<pre><code>public static string Call()
{
    string ref1 = HttpContext.Current.Request.ServerVariables["HTTP_REFERER"];
    Response.write(ref1);
}

public void Page_Load(object sender, EventArgs e)
{
    Call()
}
</code></pre>

<blockquote>
  <p>CS0120: An object reference is required for the non-static field,
  method, or property 'System.Web.UI.Page.Response.get'</p>
</blockquote>
