$form .= Xml::openElement( 'form', array( 'method' => 'get', 'action' => $wgScript ) );
$form .= Html::hidden( 'title', $this->getTitle()->getPrefixedText() );
$form .= '<p>' . Xml::inputLabel( $this->msg( 'booksources-isbn' )->text(), 'isbn', 'isbn', 20, $this->isbn );
$form .= Xml::openElement( 'form', array( 'method' => 'get', 'action' => $wgScript ) );
$form .= Html::hidden( 'title', $this->getTitle()->getPrefixedText() );
$form .= '<p>' . Xml::inputLabel( $this->msg( 'booksources-isbn' )->text(), 'isbn', 'isbn', 20, $this->isbn );