ML document is an instance of a specified XML <em>schema</em>.  An XML schema defines the
		    content model (also called a <em>grammar</em> or <em>vocabulary</em>) that its instance documents
		    will represent.
        </p>
        <p>
            There are a number of popular technologies available for creating an XML schema. Some of the most
            popular include:
            <ul>
                <li><strong>Document Type Definition (DTD)</strong> - XML's built-in schema language.</li>
        