new itemscope or not?

**Dear all,

if I want to describe a book in schema.org: Which of the following two 
versions is correct / better?

    <div itemscope itemtype ="http://schema.org/Book">
        <span itemprop="author" itemscope
    itemtype="http://schema.org/Person"><span
    itemprop="name">Shakespeare, William</span></span>
    </div>

Or just:

    <div itemscope itemtype ="http://schema.org/Book">
        <span itemprop="author">Shakespeare, William</span>
    </div>

Best,
Cord

-- 
Cord Wiljes
Semantic Computing Group
Excellence Cluster - Cognitive Interaction Technology (CITEC)
Bielefeld University

Phone: +49 521 106 12036
Mail: cwiljes@cit-ec.uni-bielefeld.de
WWW: http://www.sc.cit-ec.uni-bielefeld.de/people/wiljes

Room H-123
Morgenbreede 39
33615 Bielefeld